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单选题
Radiation can spread a fire by （）.
A
transmitting the heat of a fire through the ship s metal
B
burning liquids flowing into another space
C
heated gases flowing through ventilation systems
D
the transfer of heat across an unobstructed space
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更多 “单选题Radiation can spread a fire by （）.A transmitting the heat of a fire through the ship s metalB burning liquids flowing into another spaceC heated gases flowing through ventilation systemsD the transfer of heat across an unobstructed space” 相关考题
考题
发生火情时，客人们能用电梯吗?A.Can guests use the stairs when a fire appears?B.Can guests use the elevators when a fire presents?C.Can guests use the lifts when a fire occurs?D.Can guests use the ladders when a fire breaks up?
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Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.lt can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver.Similarly,we can't sense radioactivity without a radiation detector.But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant．This is the case when only a few cells are hit,and if they are killed outnght.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer.Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as a result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.The underlined word"significant"in Paragraph 3 most probably means______.A:fatal B:meaningfulC:remarkableD:harmful
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第三篇 Nuclear Power and Its DangerNqclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver.Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital or-gans.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.if the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead cells with healthy ones. But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce them-selves in a deformed way. They can grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done with-out the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine, then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.Radiation can cause serious consequences even at the lowest level_________.A:when it kills few cellsB:if it damages few cellsC:though the damaged cells can repair themselvesD:unless the damaged cells can reproduce themselves
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第三篇 Nuclear Power and Its DangerNqclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver.Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital or-gans.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.if the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead cells with healthy ones. But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce them-selves in a deformed way. They can grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done with-out the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine, then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.Which of the following can be best inferred from the passage?A:The importance of protection from radiation cannot be over-emphasized.B:The mystery about radiation remains unsolved.C:Cancer is mnainly caused by radiation.D:Radiation can hurt those who are not aware of its danger.
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第一篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.It can't be seen or heard,or touched or tasted,even though it may be all around us.There are other things like that. For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright,your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.Radiation can hurt us in the way that it can________.A:kill large numbers of cells in main organs so as to cause death immediatelyB:damage cells which may grow into cancer years laterC:affect the healthy growth of our offspringD:all of the above
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第一篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.It can't be seen or heard,or touched or tasted,even though it may be all around us.There are other things like that. For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright,your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.According to the passage,the danger of nuclear power lies in________.A:nuclear mysteryB:radiation detectionC:nuclear radiationD:radiation level
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第一篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.It can't be seen or heard,or touched or tasted,even though it may be all around us.There are other things like that. For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright,your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.The word"significant"in Paragraph 3 most probably means________. A:fatalB:meaningfulC:remarkableD:harmful
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共用题干
Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.lt can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver.Similarly,we can't sense radioactivity without a radiation detector.But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant．This is the case when only a few cells are hit,and if they are killed outnght.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer.Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as a result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.According to the passage,the danger of nuclear power lies in______.A:nuclear mysiery B:radiation detectionC:nuclear radiation D:radiation level
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共用题干
Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.lt can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver.Similarly,we can't sense radioactivity without a radiation detector.But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant．This is the case when only a few cells are hit,and if they are killed outnght.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer.Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as a result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.Radiation1 can cause serious consequences even at the lowest level______.A:when it kills few cellsB:if it damages few cellsC:though the damaged cells can repair themselvesD:unless the damaged cells can reproduce themselves
考题
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第三篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radia-tion.Nuclear radiation has a certain mystery about it,partly because it canhot be detected by human senses. It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way. They can grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be donewithout the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.According to the passage,the danger of nuclear power lies in___________.A:nuclear mysteryB:radiation detectionC:nuclear radiationD:radiation level
考题
共用题干
第三篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radia-tion.Nuclear radiation has a certain mystery about it,partly because it canhot be detected by human senses. It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way. They can grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be donewithout the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.Radiation can cause serious consequences even at the lowest level___________.A:when it kills few cellsB:if it damages few cellsC:though the damaged cells can repair themselvesD:unless the damaged cells can reproduce themselves
考题
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第二篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.There is a certain mystery about nuclear radiation,partly because it cannot be detected by human senses. It can't be seen or heard,or touched or tasted,even though it may be all around us. There are other things like that. For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beingsand other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright,your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.Theycan grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result. Or a child can be born weak or liable to serious illness as result of radiation absorbed by his grandparents.Radiation can hurt us.We must know the truth.Radiation can hurt us in the way that it can_______.A:kill large number of cells in main organs so as to cause death immediatelyB:damage cells which may grow into cancer years laterC:affect the healthy growth of our offspringD:all of the above
考题
共用题干
第三篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radia-tion.Nuclear radiation has a certain mystery about it,partly because it canhot be detected by human senses. It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way. They can grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be donewithout the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.Radiation can hurt us in the way that it can__________.A:kill large numbers of cells in main organs so as to cause death immediatelyB:damage cells which may grow into cancer years laterC:affect the healthy growth of our offspringD:all of the above
考题
共用题干
第二篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.There is a certain mystery about nuclear radiation,partly because it cannot be detected by human senses. It can't be seen or heard,or touched or tasted,even though it may be all around us. There are other things like that. For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beingsand other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright,your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.Theycan grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result. Or a child can be born weak or liable to serious illness as result of radiation absorbed by his grandparents.Radiation can hurt us.We must know the truth.Radiation can cause serious consequences even at the lowest level_______.A:when it kills a few cellsB:if it damages a few cellsC:though the damaged cells can repair themselvesD:if the damaged cells reproduce themselves
考题
共用题干
第二篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.There is a certain mystery about nuclear radiation,partly because it cannot be detected by human senses. It can't be seen or heard,or touched or tasted,even though it may be all around us. There are other things like that. For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beingsand other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright,your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.Theycan grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result. Or a child can be born weak or liable to serious illness as result of radiation absorbed by his grandparents.Radiation can hurt us.We must know the truth.According to the passage,the danger of nuclear power lies in_______.A:nuclear mystery B:radiation detectionC:nuclear radiation D:radiation level
考题
共用题干
第二篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.There is a certain mystery about nuclear radiation,partly because it cannot be detected by human senses. It can't be seen or heard,or touched or tasted,even though it may be all around us. There are other things like that. For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beingsand other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright,your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.Theycan grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result. Or a child can be born weak or liable to serious illness as result of radiation absorbed by his grandparents.Radiation can hurt us.We must know the truth. Which of the following can be best inferred from the passage?A:The importance of protection from radiation cannot be over-emphasized.B:The mystery about radiation remains unsolved.C:Cancer is mainly caused by radiation.D:Radiation can hurt those who are not aware of its danger.
考题
共用题干
第三篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radia-tion.Nuclear radiation has a certain mystery about it,partly because it canhot be detected by human senses. It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way. They can grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be donewithout the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.Which of the following can be best inferred from the passage?A:The importance of protection from radiation cannot be over-emphasized.B:The mystery about radiation remains unsolved.C:Cancer is mainly caused by radiation.D:Radiation can hurt those who are not aware of its danger.
考题
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第二篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.There is a certain mystery about nuclear radiation,partly because it cannot be detected by human senses. It can't be seen or heard,or touched or tasted,even though it may be all around us. There are other things like that. For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beingsand other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright,your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.Theycan grow into cancer. Sometimes this does not show up for many years.This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result. Or a child can be born weak or liable to serious illness as result of radiation absorbed by his grandparents.Radiation can hurt us.We must know the truth.The word"significant"in Paragraph 3 most probably means_______.A:fatal B:meaningfulC:remarkable D:harmful
考题
单选题In the event of a fire, the doors to a stair tower must be closed to prevent the spread of fire by （）.A
convectionB
conductionC
radiationD
ventilation
考题
单选题Fire may be spread by which means?（）A
Conduction of heat to adjacent surfacesB
Direct radiationC
ConvectionD
All of the above
考题
单选题What is meant by the term overhaul in firefighting?（）A
Slow down the spread of fire by cooling adjacent structuresB
Cover the fire with foamC
Smother the fire with a blanket or similar objectD
Break up solid objects to ensure that any deep seated fires are extinguished
考题
单选题Ventilation systems connected to a compartment in which a fire is burning are normally closed to prevent the rapid spread of the fire by（）.A
convectionB
conductionC
radiationD
spontaneous combustion
考题
单选题The blocking or absence of fire dampers can cause（）.A
the accumulation of explosive gasesB
faster cooling of the fireC
the fire to spread through the ventilation systemD
fixed foam systems to be ineffective
考题
单选题Fire dampers prevent the spread of fire by（）.A
convectionB
conductionC
radiationD
direct contact
考题
单选题The primary function(s) of an automatic sprinkler system is(are) to（）.A
extinguish the fire which triggers itB
limit the spread of fire and control the amount of heat producedC
protect people in the areas which have sprinkler headsD
alert the crew to the fire
考题
单选题Blocking open or removing fire dampers can cause（）.A
fixed foam systems to be ineffectiveB
faster cooling of the fireC
the accumulation of explosive gasesD
the fire to spread through the ventilation system
考题
单选题Radiation spreads a fire by（）.A
transferring heat across an unobstructed spaceB
heated gases flowing through ventilation systemsC
burning liquids flowing into another spaceD
transmitting the heat of a fire through the ship's metal
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