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It’s one of our common beliefs that mice are afraid of cats. Scientists have long known that even if a mouse has never seen a cat before, it is still able to detect chemical signals released from it and run away in fear. This has always been thought to be something that is hard-wired into a mouse’ s brain.
But now Wendy Ingram, a graduate student at the University of California, Berkeley, has challenged this common sense. She has found a way to “cure” mice of their inborn fear of cats by infecting them with a parasite, reported the science journal Nature.
The parasite, called Toxoplasma gondii, might sound unfamiliar to you, but the shocking fact is that up to one-third of people around the world are infected by it. This parasite can cause different diseases among humans, especially pregnant women—it is linked to blindness and the death of unborn babies.
However, the parasite’s effects on mice are unique. Ingram and her team measured how mice reacted to a cat's urine (尿) before and after it was infected by the parasite. They noted that normal mice stayed far away from the urine while mice that were infected with the parasite walked freely around the test area.
But that's not all. The parasite was found to be more powerful than originally thought—even after researchers cured the mice of the infection. They no longer reacted with fear to a cat's smell, which could indicate that the infection has caused a permanent change in mice's brains.
Why does a parasite change a mouse's brain instead of making it sick like it does to humans The answer lies in evolution.
“It’s exciting scary to know how a parasite can manipulate a mouse's brain this way,"Ingram said. But she also finds it inspiring. "Typically if you have a bacterial infection, you go to a doctor and take antibiotics and the infection is cleared and you expect all the symptoms to also go away,” she said, but this study has proven that wrong. “This may have huge implications for infectious disease medicine."

The author's attitude towards the experiment is__________.查看材料

A.positive
B.subjective
C.negative
D.objective

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参考解析
解析：在整篇文章中，作者都是在客观地叙述Wendy Ingram的新发现。positive“积极的，肯定的”；subjective“主观的”；negative“消极的，否定的”；objective“客观的”，故选D。
更多 “It’s one of our common beliefs that mice are afraid of cats. Scientists have long known that even if a mouse has never seen a cat before, it is still able to detect chemical signals released from it and run away in fear. This has always been thought to be something that is hard-wired into a mouse’ s brain. But now Wendy Ingram, a graduate student at the University of California, Berkeley, has challenged this common sense. She has found a way to “cure” mice of their inborn fear of cats by infecting them with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii, might sound unfamiliar to you, but the shocking fact is that up to one-third of people around the world are infected by it. This parasite can cause different diseases among humans, especially pregnant women—it is linked to blindness and the death of unborn babies. However, the parasite’s effects on mice are unique. Ingram and her team measured how mice reacted to a cat's urine (尿) before and after it was infected by the parasite. They noted that normal mice stayed far away from the urine while mice that were infected with the parasite walked freely around the test area. But that's not all. The parasite was found to be more powerful than originally thought—even after researchers cured the mice of the infection. They no longer reacted with fear to a cat's smell, which could indicate that the infection has caused a permanent change in mice's brains. Why does a parasite change a mouse's brain instead of making it sick like it does to humans The answer lies in evolution. “It’s exciting scary to know how a parasite can manipulate a mouse's brain this way,"Ingram said. But she also finds it inspiring. "Typically if you have a bacterial infection, you go to a doctor and take antibiotics and the infection is cleared and you expect all the symptoms to also go away,” she said, but this study has proven that wrong. “This may have huge implications for infectious disease medicine." The author's attitude towards the experiment is__________.查看材料A.positive B.subjective C.negative D.objective” 相关考题
考题 I haven't seen him for quite a long time, but his parents ______ him sometimes.A. still sawB. still seeC. have still seenD. has still seen
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考题 Passage FiveMany superstitious people are afraid of black cats. They believe that black cats have a strange power. If a black cat crosses their path, they think they will have bad luck.Black cats haven't always had such a bad reputation. Long ago, the Egyptians thought that black cats were holy animals. They even worshipped them. Pasht was an Egyptian goddess who had a woman's body and a cat's head. Because the Egyptians had so much respect for black cats, they often buried the sacred creatures with great ceremony. Mummies of cats have often been found in ancient cemetery ruins. To keep the cats company after they died, mice were sometimes buried beside them.Feelings about black cats have always been strong. People have thought they were either very good or very bad. The people of Europe, in the Middle Ages, believed black cats were the evil friends of witches and the Devil. Witches were said to have the power to change themselves into black cats. People believed that you could not tell whether a black cat was just a cat, or whether it was a witch disguising herself as she plotted some evil scheme. The brain of a black cat was thought to be a main ingredient in witch's brew.Unlike their ancestors of the Middle Ages, Englishmen today consider black cats to be good luck charms. Fishermen's wives often keep a black cat around so that their husbands will be protected when they are out at sea.52. The Egyptian goddess Pasht had a ______.A. woman's head and a cat's bodyB. woman's head and a lion's bodyC. cat's head and a man's bodyD. woman's body and a cat's head
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考题 请阅读Passage l。完成第21—25小题。 Passage 1 It's one of our common beliefs that mice are afraid of cats. Scientists have long known that even if a mouse has never seen a cat before, it is still able to detect chemical signals released from it and run away in fear. This has always been thought to be something that is hard-wired into a mouse s brain. But now Wendy Ingram, a graduate student at the University of California, Berkeley, has challenged this common sense. She has found a way to"cure" mice of their inborn fear of cats by infecting them with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii, might sound unfamiliar to you, but the shocking fact is that up to one-third of people around the world are infected by it. This parasite can cause different diseases among humans, especially pregnant women--it is linked to blindness and the death of unborn babies. However, the parasite's effects on mice are unique. Ingram and her team measured how mice reacted to a cat's urine(尿) before and after it was infected by the parasite. They noted that normal mice stayed far away from the urine while mice that were infected with the parasite walked freely around the test area. But that's not all. The parasite was found to be more powerful than originally thought—even after researchers cured the mice of the infection. They no longer reacted with fear to a cat's smell,which could indicate that the infection has caused a permanent change in mice's brains. Why does a parasite change a mouse's brain instead of making it sick like it does to humans? The answer lies in evolution. "It's exciting scary to know how a parasite can manipulate a mouse's brain this way," Ingram said. But she also finds it inspiring."Typically if you have a bacterial infection, you go to a doctor and take antibiotics and the infection is cleared and you expect all the symptoms to also go away." She said, but this study has proven that wrong."This may have huge implications for infectious disease medicine." The passage is mainly about__________. 查看材料 A．mice' s inborn terror of cats B．the evolution of Toxoplasma C．a new study about the effects of a parasite on mice D．a harmful parasite called Toxoplasma gondii
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考题 请阅读Passage l。完成第21—25小题。 Passage 1 It's one of our common beliefs that mice are afraid of cats. Scientists have long known that even if a mouse has never seen a cat before, it is still able to detect chemical signals released from it and run away in fear. This has always been thought to be something that is hard-wired into a mouse s brain. But now Wendy Ingram, a graduate student at the University of California, Berkeley, has challenged this common sense. She has found a way to"cure" mice of their inborn fear of cats by infecting them with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii, might sound unfamiliar to you, but the shocking fact is that up to one-third of people around the world are infected by it. This parasite can cause different diseases among humans, especially pregnant women--it is linked to blindness and the death of unborn babies. However, the parasite's effects on mice are unique. Ingram and her team measured how mice reacted to a cat's urine(尿) before and after it was infected by the parasite. They noted that normal mice stayed far away from the urine while mice that were infected with the parasite walked freely around the test area. But that's not all. The parasite was found to be more powerful than originally thought—even after researchers cured the mice of the infection. They no longer reacted with fear to a cat's smell,which could indicate that the infection has caused a permanent change in mice's brains. Why does a parasite change a mouse's brain instead of making it sick like it does to humans? The answer lies in evolution. "It's exciting scary to know how a parasite can manipulate a mouse's brain this way," Ingram said. But she also finds it inspiring."Typically if you have a bacterial infection, you go to a doctor and take antibiotics and the infection is cleared and you expect all the symptoms to also go away." She said, but this study has proven that wrong."This may have huge implications for infectious disease medicine." Which of the following statements is true according to the passage? 查看材料 A．Toxoplasma gondii causes people strange and deadly diseases. B．With certain infection the infectious disease cannot be cured completely. C．Human beings infected by toxoplasma gondii will have permanent brain damage. D．Toxoplasma gondii is harmful to human beings, but it does no harm to mice.
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考题 请阅读Passage l。完成第21—25小题。 Passage 1 It's one of our common beliefs that mice are afraid of cats. Scientists have long known that even if a mouse has never seen a cat before, it is still able to detect chemical signals released from it and run away in fear. This has always been thought to be something that is hard-wired into a mouse s brain. But now Wendy Ingram, a graduate student at the University of California, Berkeley, has challenged this common sense. She has found a way to"cure" mice of their inborn fear of cats by infecting them with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii, might sound unfamiliar to you, but the shocking fact is that up to one-third of people around the world are infected by it. This parasite can cause different diseases among humans, especially pregnant women--it is linked to blindness and the death of unborn babies. However, the parasite's effects on mice are unique. Ingram and her team measured how mice reacted to a cat's urine(尿) before and after it was infected by the parasite. They noted that normal mice stayed far away from the urine while mice that were infected with the parasite walked freely around the test area. But that's not all. The parasite was found to be more powerful than originally thought—even after researchers cured the mice of the infection. They no longer reacted with fear to a cat's smell,which could indicate that the infection has caused a permanent change in mice's brains. Why does a parasite change a mouse's brain instead of making it sick like it does to humans? The answer lies in evolution. "It's exciting scary to know how a parasite can manipulate a mouse's brain this way," Ingram said. But she also finds it inspiring."Typically if you have a bacterial infection, you go to a doctor and take antibiotics and the infection is cleared and you expect all the symptoms to also go away." She said, but this study has proven that wrong."This may have huge implications for infectious disease medicine." The experiment found that mice infected with toxoplasma gondii__________. 查看材料 A．stayed far away from cat's urine B．moved around the area freely and tearlessly C．because more sensitive to cat's smell D．were more afraid of cats
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考题 请阅读Passage l。完成第21—25小题。 Passage 1 It's one of our common beliefs that mice are afraid of cats. Scientists have long known that even if a mouse has never seen a cat before, it is still able to detect chemical signals released from it and run away in fear. This has always been thought to be something that is hard-wired into a mouse s brain. But now Wendy Ingram, a graduate student at the University of California, Berkeley, has challenged this common sense. She has found a way to"cure" mice of their inborn fear of cats by infecting them with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii, might sound unfamiliar to you, but the shocking fact is that up to one-third of people around the world are infected by it. This parasite can cause different diseases among humans, especially pregnant women--it is linked to blindness and the death of unborn babies. However, the parasite's effects on mice are unique. Ingram and her team measured how mice reacted to a cat's urine(尿) before and after it was infected by the parasite. They noted that normal mice stayed far away from the urine while mice that were infected with the parasite walked freely around the test area. But that's not all. The parasite was found to be more powerful than originally thought—even after researchers cured the mice of the infection. They no longer reacted with fear to a cat's smell,which could indicate that the infection has caused a permanent change in mice's brains. Why does a parasite change a mouse's brain instead of making it sick like it does to humans? The answer lies in evolution. "It's exciting scary to know how a parasite can manipulate a mouse's brain this way," Ingram said. But she also finds it inspiring."Typically if you have a bacterial infection, you go to a doctor and take antibiotics and the infection is cleared and you expect all the symptoms to also go away." She said, but this study has proven that wrong."This may have huge implications for infectious disease medicine." The author's attitude towards the experiment is__________. 查看材料 A．positive B．subjective C．negative D．objective
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考题 请阅读Passage l。完成第21—25小题。 Passage 1 It's one of our common beliefs that mice are afraid of cats. Scientists have long known that even if a mouse has never seen a cat before, it is still able to detect chemical signals released from it and run away in fear. This has always been thought to be something that is hard-wired into a mouse s brain. But now Wendy Ingram, a graduate student at the University of California, Berkeley, has challenged this common sense. She has found a way to"cure" mice of their inborn fear of cats by infecting them with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii, might sound unfamiliar to you, but the shocking fact is that up to one-third of people around the world are infected by it. This parasite can cause different diseases among humans, especially pregnant women--it is linked to blindness and the death of unborn babies. However, the parasite's effects on mice are unique. Ingram and her team measured how mice reacted to a cat's urine(尿) before and after it was infected by the parasite. They noted that normal mice stayed far away from the urine while mice that were infected with the parasite walked freely around the test area. But that's not all. The parasite was found to be more powerful than originally thought—even after researchers cured the mice of the infection. They no longer reacted with fear to a cat's smell,which could indicate that the infection has caused a permanent change in mice's brains. Why does a parasite change a mouse's brain instead of making it sick like it does to humans? The answer lies in evolution. "It's exciting scary to know how a parasite can manipulate a mouse's brain this way," Ingram said. But she also finds it inspiring."Typically if you have a bacterial infection, you go to a doctor and take antibiotics and the infection is cleared and you expect all the symptoms to also go away." She said, but this study has proven that wrong."This may have huge implications for infectious disease medicine." The underlined part "hard-wired" in Paragraph 1 probably means__________. 查看材料 A．deeply rooted B．quickly changed C．closely linked D．deeply hurried
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考题 共用题干 第一篇A meager（不足的）diet may give you health and long life, but it's not much fun一and it might not even be necessary. We may be able to hang on to most of that youthful（有青春活力的）vigor （精力）even if we don't start to diet until old age.Stephen Spindler and his colleagues from the University of California at Riverside have found that some of an elderly mouse's liver genes can be made to behave as they did when the mouse was young simply by limiting its food for four weeks. The genetic rejuvenation（恢复活力，返老还童） won't reverse other damage caused by time for the mouse,but could help its liver metabolize（使进入新陈代谢过程）drugs or get rid of toxins.Spindler's team fed three mice a normal diet for their whole lives,and fed another three on half-rations.Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old一equivalent to about 70 human years.The researchers checked the activity of 11,000 genes from the mouse livers,and found that 46 changed with age in the normally fed mice.The changes were associated with things like inflammation and free radical production一probably bad news for mouse health.In the mice that had dieted all their lives,27 of those 46 genes continued to behave like young genes.But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 percent of these gene changes."This is the first indication that these effects kick in pretty quickly",says Huber Warner from the National Institute on Aging near Washington D.C.No one yet knows if calorie restriction works in people as it does in mice,but Spindler is hopeful."There's attracting and tempting evidence out there that it will work,"he says.If it does work in people,there might be good reasons for rejuvenating the liver. As we get older,our bodies are less efficient at metabolizing drugs,for example.A brief period of time of dieting,says Spindler,could be enough to make sure a. drug is effective.But Spindler isn't sure the trade-off is worth it."The mice get less disease,they live longer,but they're hungry,"he says."Even seeing what a diet does,it's still hard to go to a restaurant and say:I can only eat half of that."Spindler hopes we soon won't need to diet at all. His company,Lifespan Genetics in California, is looking for drugs that have the effects of calorie restriction.Why does the author mention an elderly mouse in paragraph 2?A:To describe the influence of old age on mice.B:To illustrate the effect of meager food on mice.C:To tell us how mice's liver genes behave.D:To inform us of the process of metabolizing drugs.
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考题 共用题干 第一篇A meager（不足的）diet may give you health and long life, but it's not much fun一and it might not even be necessary. We may be able to hang on to most of that youthful（有青春活力的）vigor （精力）even if we don't start to diet until old age.Stephen Spindler and his colleagues from the University of California at Riverside have found that some of an elderly mouse's liver genes can be made to behave as they did when the mouse was young simply by limiting its food for four weeks. The genetic rejuvenation（恢复活力，返老还童） won't reverse other damage caused by time for the mouse,but could help its liver metabolize（使进入新陈代谢过程）drugs or get rid of toxins.Spindler's team fed three mice a normal diet for their whole lives,and fed another three on half-rations.Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old一equivalent to about 70 human years.The researchers checked the activity of 11,000 genes from the mouse livers,and found that 46 changed with age in the normally fed mice.The changes were associated with things like inflammation and free radical production一probably bad news for mouse health.In the mice that had dieted all their lives,27 of those 46 genes continued to behave like young genes.But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 percent of these gene changes."This is the first indication that these effects kick in pretty quickly",says Huber Warner from the National Institute on Aging near Washington D.C.No one yet knows if calorie restriction works in people as it does in mice,but Spindler is hopeful."There's attracting and tempting evidence out there that it will work,"he says.If it does work in people,there might be good reasons for rejuvenating the liver. As we get older,our bodies are less efficient at metabolizing drugs,for example.A brief period of time of dieting,says Spindler,could be enough to make sure a. drug is effective.But Spindler isn't sure the trade-off is worth it."The mice get less disease,they live longer,but they're hungry,"he says."Even seeing what a diet does,it's still hard to go to a restaurant and say:I can only eat half of that."Spindler hopes we soon won't need to diet at all. His company,Lifespan Genetics in California, is looking for drugs that have the effects of calorie restriction.What can be inferred about completely normally fed mice mentioned in the passage?A:They will not experience free radical production.B:They will experience more genetic rejuvenation in their lifetime.C:They have more old liver genes to behave like young genes.D:They are more likely to suffer from inflammation.
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考题 共用题干 第二篇Natural MedicinesSince earliest days,humans have used some kinds of medicines.We know this because humans have survived.Ancient treatments for injury and disease were successful enough to keep humans from dying out completely.They were successful long before the time of modern medicine.Before the time of doctors with white coats and shiny（发亮的）instruments. Before the time of big hospitals with strange and wonderful equipment.Many parts of the world still do not have university-educated doctors. Nor do they have expensive hospi- tals.Yet injuries are treated.And diseases are often cured.How?By ancient methods.By medicines that might seem mysterious , even magical（有魔力的）.Traditional medicines are neither mysterious nor magical, however.Through the centuries, tribal（部族的）medicine men experimented with plants. They found many use- ful chemicals in the plants.And scientists believe many of these traditional medicines may provide the cure for some of today's most serious diseases.Experts say almost 80% of the people in the world use plants for health care.These natural medicines are used not just because people have no other form of treatment.They are used because people trust them. In developed areas,few people think about the source of the medicines they buy in a store.Yet many wide- ly-used medicines are from ancient sources,especially plants.Some experts say more than 25% of modern medicines come,in one way or another,from nature.Scientists have long known that nature is really a chemical factory.All living things contain chemicals that help them survive.So scientists' interest in traditional medicine is not new.But it has become an ur-gent concern.This is because the earth's supply of natural medicines may be dropping rapidly. It can be seen from the passage that the earth's supply of natural medicines________.A:may never be exhaustedB:may be dropping rapidlyC:is surprisingly bigD:is as rich as ever
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考题 共用题干 第一篇A meager（不足的）diet may give you health and long life, but it's not much fun一and it might not even be necessary. We may be able to hang on to most of that youthful（有青春活力的）vigor （精力）even if we don't start to diet until old age.Stephen Spindler and his colleagues from the University of California at Riverside have found that some of an elderly mouse's liver genes can be made to behave as they did when the mouse was young simply by limiting its food for four weeks. The genetic rejuvenation（恢复活力，返老还童） won't reverse other damage caused by time for the mouse,but could help its liver metabolize（使进入新陈代谢过程）drugs or get rid of toxins.Spindler's team fed three mice a normal diet for their whole lives,and fed another three on half-rations.Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old一equivalent to about 70 human years.The researchers checked the activity of 11,000 genes from the mouse livers,and found that 46 changed with age in the normally fed mice.The changes were associated with things like inflammation and free radical production一probably bad news for mouse health.In the mice that had dieted all their lives,27 of those 46 genes continued to behave like young genes.But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 percent of these gene changes."This is the first indication that these effects kick in pretty quickly",says Huber Warner from the National Institute on Aging near Washington D.C.No one yet knows if calorie restriction works in people as it does in mice,but Spindler is hopeful."There's attracting and tempting evidence out there that it will work,"he says.If it does work in people,there might be good reasons for rejuvenating the liver. As we get older,our bodies are less efficient at metabolizing drugs,for example.A brief period of time of dieting,says Spindler,could be enough to make sure a. drug is effective.But Spindler isn't sure the trade-off is worth it."The mice get less disease,they live longer,but they're hungry,"he says."Even seeing what a diet does,it's still hard to go to a restaurant and say:I can only eat half of that."Spindler hopes we soon won't need to diet at all. His company,Lifespan Genetics in California, is looking for drugs that have the effects of calorie restriction.According to the last two paragraphs,Spindler believes that__________.A:calorie restriction is very important to young people.B:seeing the effect of a diet,people will like to eat less than normal.C:dieting is not a good method to give us health and long life.D:drugs do not have the effects of calorie restriction.
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考题 共用题干 Natural MedicinesSince earliest days,humans have used some kinds of medicines.We know this because hu-mans have survived .Ancient treatments for injury and disease were successful enough to keep hu-mans from dying out completely.They were successful long before the time of modern medicine.Before the time of doctors with white coats and shiny（发亮的）instruments. Before the time of big hospitals with strange and wonderful equipment.Many parts of the world still do not have university-educated doctors.Nor do they have ex- pensive hospitals.Yet injuries are treated.And diseases are often cured.How?By ancient meth- ods. By medicines that might seem mysterious, even magical（有魔力的）.Traditional medicines are neither mysterious nor magical,however.Through the centuries, tribal（部落的）medicine men experimented with plants. They found many useful chemicals in the plants.And scientists believe many of these traditional medicines may provide the cure for some of today's most serious diseases.Experts say almost 80%of the people in the world use plants for health care.These natural medicines are used not just because people have no other form of treatment.They are used be-cause people trust them.In developed areas,few people think about the source of the medicines they buy in a store.Yet many widely-used medicines are from ancient sources,especially plants. Some experts say more than 25%of modern medicines come,in one way or another,from nature.Scientists have long known that nature is really a chemical factory.All living things contain chemicals that help them survive .So scientists' interest in traditional medicine is not new.But it has become an urgent concern.This is because the earth's supply of natural medicines may be dropping rapidly. It is believed by scientists that traditional medicines______.A:cancureallkindsofdiseasesB: maycuresomeoftoday,smostseriousdiseasesC: arenolongerusefulformodernmenD: aretoocheaptoheuseful
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考题 共用题干 Natural MedicinesSince earliest days,humans have used some kinds of medicines.We know this because hu-mans have survived .Ancient treatments for injury and disease were successful enough to keep hu-mans from dying out completely.They were successful long before the time of modern medicine.Before the time of doctors with white coats and shiny（发亮的）instruments. Before the time of big hospitals with strange and wonderful equipment.Many parts of the world still do not have university-educated doctors.Nor do they have ex- pensive hospitals.Yet injuries are treated.And diseases are often cured.How?By ancient meth- ods. By medicines that might seem mysterious, even magical（有魔力的）.Traditional medicines are neither mysterious nor magical,however.Through the centuries, tribal（部落的）medicine men experimented with plants. They found many useful chemicals in the plants.And scientists believe many of these traditional medicines may provide the cure for some of today's most serious diseases.Experts say almost 80%of the people in the world use plants for health care.These natural medicines are used not just because people have no other form of treatment.They are used be-cause people trust them.In developed areas,few people think about the source of the medicines they buy in a store.Yet many widely-used medicines are from ancient sources,especially plants. Some experts say more than 25%of modern medicines come,in one way or another,from nature.Scientists have long known that nature is really a chemical factory.All living things contain chemicals that help them survive .So scientists' interest in traditional medicine is not new.But it has become an urgent concern.This is because the earth's supply of natural medicines may be dropping rapidly. It can be seen from the passage that the earth,5 supply of natural medicines_______.A: mayneverbeexhaustedB: maybedroppingrapidlyC: issurprisinglybigD: isasrichasever
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考题 资料：It’s easy to trace the evolution of the automobile.At most，we’re only talking about a few centuries of technological development，and most of the plans，prototypes and models are still around. With just a little research，you can easily trace the latest model electric hybrid back to its steam-powered ancestors. Your family tree is probably a different matter. Even an extensive genealogy chart can only reach back so far，and mortality puts a rather strict limit on exactly how many “models” are still on the road. Humanity’s evolutionary progression is even more difficult. We still have plenty of living primate relatives，but many of the life forms that connect the evolutionary dots are long extinct. Evolutionary biologists use several methods to decipher exactly how we came to be as we are.In fact，the field itself encompasses several different disciplines in addition to biology，like genetics，psychology，geology，archaeology linguistics，anthropology and primatology just to name a few. Naturally，paleoanthropology also plays a key role，as we have to turn to the fossil record for many clues about our ancient primate，human and nearly human ancestors. While the fossil record by its very nature is incomplete，there’s no shortage of fossil evidence to link the planet’s varied life forms into a great tree of life， a chart that scientists call a phylogenetic tree. You can think of humans as the very tip of just one branch on that tree called “hominid.” Chimpanzees exist at the end of an adjoining branch called “panin.” Follow both the hominid and panin branch back about 5.4 million years， and you’ll find a point where scientists think the two converged from a single，common ancestor. Fossil evidence helps scientists to reconstruct these trees，but so do morphological and genetic studlies. Genetic analysis has yielded striking similarities between chimps and humans. As such， scientists know a last common ancestor of chimps and humans existed，even if we’ve yet to determine the exact species. Yet paleoanthropologists have found numerous hominid fossils to bridge the evolutionary progression from that unknown common ancestor to modern humans. These finds include such famous East African fossils as Lucy（Australopithecus afarensis），which strengthened the importance of bipedalism in human evolution and proved an essential milestone on our way to modern Homo sapiens. Fossil evidence for human evolution will never be complete，as fossils themselves are rare geologic occurrences.Nevertheless，by incorporating other scientific disciplines，we’re able to build an increasingly accurate picture of just what our evolutionary family tree consisted of. What can be inferred from Para.5?A.Morpholoical and genetic studies helped scientists to trace unknown common ancestor of chimps and humans existed. B.Morphological and genetic studies determined exact species of common ancestor of chimps and humans existed. C.Genetic studies found hominid fossils to bridge the evolutionary progression from unknown common ancestor to modern humans. D.Morphological studies helped finding the famous East African fossils and set up an milestone in this field.
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考题 共用题干 Natural MedicinesSince earliest days,humans have used some kinds of medicines.We know this because humans have survived.Ancient treatments for injury and disease were successful enough to keep humans from dying out completely.They were successful long before the time of modern medicine. Before the time of doctors with white coats and shiny（发亮的）instruments. Before the time of big hospitals with strange and wonderful equipment.Many parts of the world still do not have university-educated doctors. Nor do they have expensive hospitals.Yet injuries are treated.And diseases are often cured.How?By ancient methods. By medicines that might seem mysterious , even magical（有魔力的）.Traditional medicines are neither mysterious nor magical,however.Through the centuries , tribal（部落的）medicine men experimented with plants. They found many useful chemicals in the plants.And scientists believe many of these traditional medicines may provide the cure for some of today's most serious diseases.Experts say almost 80% of the people in the world use plants for health care.These natural medicines are used not just because people have no other form of treatment. They are used because people trust them. In developed areas,few people think about the source of the medicines they buy in a store .Yet many widely-used medicines are from ancient sources,especially plants.Some experts say more than 25%of modem medicines come,in one way or another,from nature.Scientists have long known that nature is really a chemical factory. All living things contain chemicals that help them survive .So scientists' interest in traditional medicine is not new.But it has become an urgent concern.This is because the earth's supply of natural medicines may be dropping rapidly. It is believed by scientists that traditional medicines______.A: can cure all kinds of diseasesB: may cure some of today's most serious diseasesC: are no longer useful for modern menD: are too cheap to be useful
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考题 共用题干 Natural MedicinesSince earliest days,humans have used some kinds of medicines.We know this because humans have survived.Ancient treatments for injury and disease were successful enough to keep humans from dying out completely.They were successful long before the time of modern medicine. Before the time of doctors with white coats and shiny（发亮的）instruments. Before the time of big hospitals with strange and wonderful equipment.Many parts of the world still do not have university-educated doctors. Nor do they have expensive hospitals.Yet injuries are treated.And diseases are often cured.How?By ancient methods. By medicines that might seem mysterious , even magical（有魔力的）.Traditional medicines are neither mysterious nor magical,however.Through the centuries , tribal（部落的）medicine men experimented with plants. They found many useful chemicals in the plants.And scientists believe many of these traditional medicines may provide the cure for some of today's most serious diseases.Experts say almost 80% of the people in the world use plants for health care.These natural medicines are used not just because people have no other form of treatment. They are used because people trust them. In developed areas,few people think about the source of the medicines they buy in a store .Yet many widely-used medicines are from ancient sources,especially plants.Some experts say more than 25%of modem medicines come,in one way or another,from nature.Scientists have long known that nature is really a chemical factory. All living things contain chemicals that help them survive .So scientists' interest in traditional medicine is not new.But it has become an urgent concern.This is because the earth's supply of natural medicines may be dropping rapidly. It can be seen from the passage that the earth's supply of natural medicines______.A: may never be exhaustedB: may be dropping rapidlyC: is surprisingly bigD: is as rich as ever
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考题 共用题干 Eat to LiveA meager diet may give you health and long life,but it's not much fun-and it might not even be necessary.We may be able to hang on to most of that youthful vigor even if we don't start to diet until old age.Stephen Spindler and his colleagues from the University of California at Riverside have found that some of an elderly mouse's liver genes can be made to behave as they did when the mouse was young simply by limiting its food for four weeks.The genetic rejuvenation won't reverse other damage caused by time for the mouse,but could help its liver metabolize drugs or get rid of toxins.Spindler's team fed three mice a normal diet for their whole lives,and fed another three on half-rations.Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old-equivalent to about 70 human years.The researchers checked the activity of 11,000 genes from the mouse livers,and found that-46 changed with age in the normally fed mice.The changes were associated with things like inflammation and free radical production-probably bad news for mouse health .In the mice that had dieted all their lives,27 of those 46 genes continued to behave like young genes. But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 percent of these gene changes."This is the first indication that these effects kick in pretty quickly,"says Huber Warner from the National Institute on Aging near Washington D.C.No one yet knows if calorie restriction works in people as it does in mice,but Spindler is hopeful."There's attracting and tempting evidence out there that it will work,"he says.If it does work in people,there might be good reasons for rejuvenating the liver. As we get ol- der,our bodies are less efficient at metabolizing drugs,for example.A brief period of time of die- ting,says Spindler,could be enough to make sure a drug is effective.But Spindler isn't sure the trade-off is worth it."The mice get less disease,they live longer,but they're hungry,"he says."Even seeing what a diet does,it's still hard to go to a restaurant and say:‘I can only eat half of that.’"Spindler hopes we soon won't need to diet at all.His company,Lifespan Genetics in California,is looking for drugs that have the effects of calorie restriction. What can be inferred about completely normally fed mice mentioned in the passage?A: They will not experience free radical production.B: They will experience more genetic rejuvenation in their lifetime.C: They have more old liver genes to behave like young genes.D: They are more likely to suffer from inflammation.
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考题 共用题干 Eat to LiveA meager diet may give you health and long life,but it's not much fun-and it might not even be necessary.We may be able to hang on to most of that youthful vigor even if we don't start to diet until old age.Stephen Spindler and his colleagues from the University of California at Riverside have found that some of an elderly mouse's liver genes can be made to behave as they did when the mouse was young simply by limiting its food for four weeks.The genetic rejuvenation won't reverse other damage caused by time for the mouse,but could help its liver metabolize drugs or get rid of toxins.Spindler's team fed three mice a normal diet for their whole lives,and fed another three on half-rations.Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old-equivalent to about 70 human years.The researchers checked the activity of 11,000 genes from the mouse livers,and found that-46 changed with age in the normally fed mice.The changes were associated with things like inflammation and free radical production-probably bad news for mouse health .In the mice that had dieted all their lives,27 of those 46 genes continued to behave like young genes. But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 percent of these gene changes."This is the first indication that these effects kick in pretty quickly,"says Huber Warner from the National Institute on Aging near Washington D.C.No one yet knows if calorie restriction works in people as it does in mice,but Spindler is hopeful."There's attracting and tempting evidence out there that it will work,"he says.If it does work in people,there might be good reasons for rejuvenating the liver. As we get ol- der,our bodies are less efficient at metabolizing drugs,for example.A brief period of time of die- ting,says Spindler,could be enough to make sure a drug is effective.But Spindler isn't sure the trade-off is worth it."The mice get less disease,they live longer,but they're hungry,"he says."Even seeing what a diet does,it's still hard to go to a restaurant and say:‘I can only eat half of that.’"Spindler hopes we soon won't need to diet at all.His company,Lifespan Genetics in California,is looking for drugs that have the effects of calorie restriction. According to the passage,which of the following is NOT true?A: Eating less than usual might make us live longer.B:If we go on a diet when old,we may keep healthy.C: Dieting might not be needed.D: We have to begin dieting since childhood.
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考题 共用题干 Eat to LiveA meager diet may give you health and long life,but it's not much fun-and it might not even be necessary.We may be able to hang on to most of that youthful vigor even if we don't start to diet until old age.Stephen Spindler and his colleagues from the University of California at Riverside have found that some of an elderly mouse's liver genes can be made to behave as they did when the mouse was young simply by limiting its food for four weeks.The genetic rejuvenation won't reverse other damage caused by time for the mouse,but could help its liver metabolize drugs or get rid of toxins.Spindler's team fed three mice a normal diet for their whole lives,and fed another three on half-rations.Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old-equivalent to about 70 human years.The researchers checked the activity of 11,000 genes from the mouse livers,and found that-46 changed with age in the normally fed mice.The changes were associated with things like inflammation and free radical production-probably bad news for mouse health .In the mice that had dieted all their lives,27 of those 46 genes continued to behave like young genes. But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 percent of these gene changes."This is the first indication that these effects kick in pretty quickly,"says Huber Warner from the National Institute on Aging near Washington D.C.No one yet knows if calorie restriction works in people as it does in mice,but Spindler is hopeful."There's attracting and tempting evidence out there that it will work,"he says.If it does work in people,there might be good reasons for rejuvenating the liver. As we get ol- der,our bodies are less efficient at metabolizing drugs,for example.A brief period of time of die- ting,says Spindler,could be enough to make sure a drug is effective.But Spindler isn't sure the trade-off is worth it."The mice get less disease,they live longer,but they're hungry,"he says."Even seeing what a diet does,it's still hard to go to a restaurant and say:‘I can only eat half of that.’"Spindler hopes we soon won't need to diet at all.His company,Lifespan Genetics in California,is looking for drugs that have the effects of calorie restriction. Why does the author mention an elderly mouse in paragraph 2?A: To describe the influence of old age on mice.B: To illustrate the effect of meager food on mice.C: To tell us how mice's liver genes behave.D: To inform us of the process of metabolizing drugs.
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考题 共用题干 Eat to LiveA meager diet may give you health and long life,but it's not much fun-and it might not even be necessary.We may be able to hang on to most of that youthful vigor even if we don't start to diet until old age.Stephen Spindler and his colleagues from the University of California at Riverside have found that some of an elderly mouse's liver genes can be made to behave as they did when the mouse was young simply by limiting its food for four weeks.The genetic rejuvenation won't reverse other damage caused by time for the mouse,but could help its liver metabolize drugs or get rid of toxins.Spindler's team fed three mice a normal diet for their whole lives,and fed another three on half-rations.Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old-equivalent to about 70 human years.The researchers checked the activity of 11,000 genes from the mouse livers,and found that-46 changed with age in the normally fed mice.The changes were associated with things like inflammation and free radical production-probably bad news for mouse health .In the mice that had dieted all their lives,27 of those 46 genes continued to behave like young genes. But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 percent of these gene changes."This is the first indication that these effects kick in pretty quickly,"says Huber Warner from the National Institute on Aging near Washington D.C.No one yet knows if calorie restriction works in people as it does in mice,but Spindler is hopeful."There's attracting and tempting evidence out there that it will work,"he says.If it does work in people,there might be good reasons for rejuvenating the liver. As we get ol- der,our bodies are less efficient at metabolizing drugs,for example.A brief period of time of die- ting,says Spindler,could be enough to make sure a drug is effective.But Spindler isn't sure the trade-off is worth it."The mice get less disease,they live longer,but they're hungry,"he says."Even seeing what a diet does,it's still hard to go to a restaurant and say:‘I can only eat half of that.’"Spindler hopes we soon won't need to diet at all.His company,Lifespan Genetics in California,is looking for drugs that have the effects of calorie restriction. According to the last two paragraphs,Spindler believes that______.A: drugs do not have the effects of calorie restrictionB: dieting is not a good method to give us health and long lifeC: seeing the effect of a diet,people will like to eat less than normalD: calorie restriction is very important to young people
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考题 共用题干 Eat to LiveA meager diet may give you health and long life,but it's not much fun-and it might not even be necessary.We may be able to hang on to most of that youthful vigor even if we don't start to diet until old age.Stephen Spindler and his colleagues from the University of California at Riverside have found that some of an elderly mouse's liver genes can be made to behave as they did when the mouse was young simply by limiting its food for four weeks.The genetic rejuvenation won't reverse other damage caused by time for the mouse,but could help its liver metabolize drugs or get rid of toxins.Spindler's team fed three mice a normal diet for their whole lives,and fed another three on half-rations.Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old-equivalent to about 70 human years.The researchers checked the activity of 11,000 genes from the mouse livers,and found that-46 changed with age in the normally fed mice.The changes were associated with things like inflammation and free radical production-probably bad news for mouse health .In the mice that had dieted all their lives,27 of those 46 genes continued to behave like young genes. But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 percent of these gene changes."This is the first indication that these effects kick in pretty quickly,"says Huber Warner from the National Institute on Aging near Washington D.C.No one yet knows if calorie restriction works in people as it does in mice,but Spindler is hopeful."There's attracting and tempting evidence out there that it will work,"he says.If it does work in people,there might be good reasons for rejuvenating the liver. As we get ol- der,our bodies are less efficient at metabolizing drugs,for example.A brief period of time of die- ting,says Spindler,could be enough to make sure a drug is effective.But Spindler isn't sure the trade-off is worth it."The mice get less disease,they live longer,but they're hungry,"he says."Even seeing what a diet does,it's still hard to go to a restaurant and say:‘I can only eat half of that.’"Spindler hopes we soon won't need to diet at all.His company,Lifespan Genetics in California,is looking for drugs that have the effects of calorie restriction. According to the author,which of the following most interested the researchers?A: The mice that started dieting in old age.B: 27 of those 46 old genes that continued to behave like young genes.C: Calorie restriction that works in people.D: Dieting that makes sure a drug is effective.
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考题 It’s one of our common beliefs that mice are afraid of cats. Scientists have long known that even if a mouse has never seen a cat before, it is still able to detect chemical signals released from it and run away in fear. This has always been thought to be something that is hard-wired into a mouse’ s brain. But now Wendy Ingram, a graduate student at the University of California, Berkeley, has challenged this common sense. She has found a way to “cure” mice of their inborn fear of cats by infecting them with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii, might sound unfamiliar to you, but the shocking fact is that up to one-third of people around the world are infected by it. This parasite can cause different diseases among humans, especially pregnant women—it is linked to blindness and the death of unborn babies. However, the parasite’s effects on mice are unique. Ingram and her team measured how mice reacted to a cat's urine (尿) before and after it was infected by the parasite. They noted that normal mice stayed far away from the urine while mice that were infected with the parasite walked freely around the test area. But that's not all. The parasite was found to be more powerful than originally thought—even after researchers cured the mice of the infection. They no longer reacted with fear to a cat's smell, which could indicate that the infection has caused a permanent change in mice's brains. Why does a parasite change a mouse's brain instead of making it sick like it does to humans The answer lies in evolution. “It’s exciting scary to know how a parasite can manipulate a mouse's brain this way,"Ingram said. But she also finds it inspiring. "Typically if you have a bacterial infection, you go to a doctor and take antibiotics and the infection is cleared and you expect all the symptoms to also go away,” she said, but this study has proven that wrong. “This may have huge implications for infectious disease medicine." Which of the following statements is true according to the passage 查看材料A.Toxoplasma gondii causes people strange and deadly diseases. B.With certain infection the infectious disease cannot be cured completely. C.Human beings infected by toxoplasma gondii will have permanent brain damage. D.Toxoplasma gondii is harmful to human beings, but it does no harm to mice.
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考题 根据以下材料，回答 It′s one of our common beliefs that miceare afraid of cats. Scientists have long known that even if a mouse has neverseen a cat before, it is still able to detect chemical signals released from itand run away in fear. This has always been thought to be something that is hard-wiredinto a mouse′ s brain. But now Wendy Ingram, a graduate student atthe University of California, Berkeley, has challenged this common sense. Shehas found a way to "cure" mice of their inborn fear of cats by infectingthem with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii,might sound unfamiliar to you, but the shocking fact is that up to one-third ofpeople around the world are infected by it. This parasite can cause different diseasesamong humans, especially pregnant women--it is linked to blindness and thedeath of unborn babies. However, the parasite′s effects on mice areunique, Ingram and her team measured how mice reacted to a cat′ s urine (尿) before and after it was infected by the parasite. They noted thatnormal mice stayed far away from the urine while mice that were infected withthe parasite walked freely around the test area. But that′s not all. The parasite was foundto be more powerful than originally thought--even after researchers cured themice of the infection. They no longer reacted with fear to a cat′s smell, whichcould indicate that the infection has caused a permanent change in mice′ sbrains. Why does a parasite change a mouse′s braininstead of making it sick like it does to humans? The answer lies in evolution. "It′s exciting scary to know how aparasite can manipulate a mouse′s brain this way," Ingram said. But shealso finds it inspiring. "Typically if you have a bacterial infection, you go to a doctor andtake antibiotics and the infection is cleared and you expect all the symptomsto also go away." She said, but this study has proven that wrong. "This may have huge implicationsfor infectious disease medicine." The experiment found that mice infectedwith toxoplasma gondii ____________.A.stayed far away from cat' s urine B.moved around the area freely andfearlessly C.because more sensitive to cat' s smell D.were more afraid of cats
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考题 根据以下材料，回答 It′s one of our common beliefs that miceare afraid of cats. Scientists have long known that even if a mouse has neverseen a cat before, it is still able to detect chemical signals released from itand run away in fear. This has always been thought to be something that is hard-wiredinto a mouse′ s brain. But now Wendy Ingram, a graduate student atthe University of California, Berkeley, has challenged this common sense. Shehas found a way to "cure" mice of their inborn fear of cats by infectingthem with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii,might sound unfamiliar to you, but the shocking fact is that up to one-third ofpeople around the world are infected by it. This parasite can cause different diseasesamong humans, especially pregnant women--it is linked to blindness and thedeath of unborn babies. However, the parasite′s effects on mice areunique, Ingram and her team measured how mice reacted to a cat′ s urine (尿) before and after it was infected by the parasite. They noted thatnormal mice stayed far away from the urine while mice that were infected withthe parasite walked freely around the test area. But that′s not all. The parasite was foundto be more powerful than originally thought--even after researchers cured themice of the infection. They no longer reacted with fear to a cat′s smell, whichcould indicate that the infection has caused a permanent change in mice′ sbrains. Why does a parasite change a mouse′s braininstead of making it sick like it does to humans? The answer lies in evolution. "It′s exciting scary to know how aparasite can manipulate a mouse′s brain this way," Ingram said. But shealso finds it inspiring. "Typically if you have a bacterial infection, you go to a doctor andtake antibiotics and the infection is cleared and you expect all the symptomsto also go away." She said, but this study has proven that wrong. "This may have huge implicationsfor infectious disease medicine." The author′s attitude towards theexperiment is ____________.A.positive B.subjective C.negative D.objective
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考题 根据以下材料，回答 It′s one of our common beliefs that miceare afraid of cats. Scientists have long known that even if a mouse has neverseen a cat before, it is still able to detect chemical signals released from itand run away in fear. This has always been thought to be something that is hard-wiredinto a mouse′ s brain. But now Wendy Ingram, a graduate student atthe University of California, Berkeley, has challenged this common sense. Shehas found a way to "cure" mice of their inborn fear of cats by infectingthem with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii,might sound unfamiliar to you, but the shocking fact is that up to one-third ofpeople around the world are infected by it. This parasite can cause different diseasesamong humans, especially pregnant women--it is linked to blindness and thedeath of unborn babies. However, the parasite′s effects on mice areunique, Ingram and her team measured how mice reacted to a cat′ s urine (尿) before and after it was infected by the parasite. They noted thatnormal mice stayed far away from the urine while mice that were infected withthe parasite walked freely around the test area. But that′s not all. The parasite was foundto be more powerful than originally thought--even after researchers cured themice of the infection. They no longer reacted with fear to a cat′s smell, whichcould indicate that the infection has caused a permanent change in mice′ sbrains. Why does a parasite change a mouse′s braininstead of making it sick like it does to humans? The answer lies in evolution. "It′s exciting scary to know how aparasite can manipulate a mouse′s brain this way," Ingram said. But shealso finds it inspiring. "Typically if you have a bacterial infection, you go to a doctor andtake antibiotics and the infection is cleared and you expect all the symptomsto also go away." She said, but this study has proven that wrong. "This may have huge implicationsfor infectious disease medicine." Which of the following statements istrue according to the passage?A.Toxoplasma gondii causes people strangeand deadly diseases. B.With certain infection the infectiousdisease cannot be cured completely. C.Human beings infected by toxoplasmagondii will have permanent brain damage. D.Toxoplasma gondii is harmful to humanbeings, but it does no harm to mice.
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考题 根据以下材料，回答 It′s one of our common beliefs that miceare afraid of cats. Scientists have long known that even if a mouse has neverseen a cat before, it is still able to detect chemical signals released from itand run away in fear. This has always been thought to be something that is hard-wiredinto a mouse′ s brain. But now Wendy Ingram, a graduate student atthe University of California, Berkeley, has challenged this common sense. Shehas found a way to "cure" mice of their inborn fear of cats by infectingthem with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii,might sound unfamiliar to you, but the shocking fact is that up to one-third ofpeople around the world are infected by it. This parasite can cause different diseasesamong humans, especially pregnant women--it is linked to blindness and thedeath of unborn babies. However, the parasite′s effects on mice areunique, Ingram and her team measured how mice reacted to a cat′ s urine (尿) before and after it was infected by the parasite. They noted thatnormal mice stayed far away from the urine while mice that were infected withthe parasite walked freely around the test area. But that′s not all. The parasite was foundto be more powerful than originally thought--even after researchers cured themice of the infection. They no longer reacted with fear to a cat′s smell, whichcould indicate that the infection has caused a permanent change in mice′ sbrains. Why does a parasite change a mouse′s braininstead of making it sick like it does to humans? The answer lies in evolution. "It′s exciting scary to know how aparasite can manipulate a mouse′s brain this way," Ingram said. But shealso finds it inspiring. "Typically if you have a bacterial infection, you go to a doctor andtake antibiotics and the infection is cleared and you expect all the symptomsto also go away." She said, but this study has proven that wrong. "This may have huge implicationsfor infectious disease medicine." The passage is mainly about____________.A.mice's inborn terror of cats B.the evolution of Toxoplasma C.a new study about the effects of aparasite on mice D.a harmful parasite called Toxoplasmagondii
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考题 根据以下材料，回答 It′s one of our common beliefs that miceare afraid of cats. Scientists have long known that even if a mouse has neverseen a cat before, it is still able to detect chemical signals released from itand run away in fear. This has always been thought to be something that is hard-wiredinto a mouse′ s brain. But now Wendy Ingram, a graduate student atthe University of California, Berkeley, has challenged this common sense. Shehas found a way to "cure" mice of their inborn fear of cats by infectingthem with a parasite, reported the science journal Nature. The parasite, called Toxoplasma gondii,might sound unfamiliar to you, but the shocking fact is that up to one-third ofpeople around the world are infected by it. This parasite can cause different diseasesamong humans, especially pregnant women--it is linked to blindness and thedeath of unborn babies. However, the parasite′s effects on mice areunique, Ingram and her team measured how mice reacted to a cat′ s urine (尿) before and after it was infected by the parasite. They noted thatnormal mice stayed far away from the urine while mice that were infected withthe parasite walked freely around the test area. But that′s not all. The parasite was foundto be more powerful than originally thought--even after researchers cured themice of the infection. They no longer reacted with fear to a cat′s smell, whichcould indicate that the infection has caused a permanent change in mice′ sbrains. Why does a parasite change a mouse′s braininstead of making it sick like it does to humans? The answer lies in evolution. "It′s exciting scary to know how aparasite can manipulate a mouse′s brain this way," Ingram said. But shealso finds it inspiring. "Typically if you have a bacterial infection, you go to a doctor andtake antibiotics and the infection is cleared and you expect all the symptomsto also go away." She said, but this study has proven that wrong. "This may have huge implicationsfor infectious disease medicine." The underlined part"hard-wired" in Paragraph 1 probably means ____________.A.deeply rooted B.quickly changed C.closely linked D.deeply hurried
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