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Questions 21 to 25 are based on the following passage. Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation worldwide has decreased significantly. A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining. In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States. In a study published in the journal Ambio, scientists found that lead levels in soil in the Northeastern United States had decreased markedly since the introduction of unleaded gasoline. Many scientists had believed that the lead would stay in soil and snow for a longer period. The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected. Scientists say both studies demonstrate that certain parts of the ecosystem (生态系统) respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute. The authors of the Ambio study have found that（）
- A、forests get rid of lead pollution faster than expected
- B、lead accumulations in forests are more difficult to deal with
- C、lead deposits are widely distributed in the forests of the US
- D、the upper layers of soil in forests are easily polluted by lead emissions
参考答案
更多 “ Questions 21 to 25 are based on the following passage. Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation worldwide has decreased significantly. A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining. In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States. In a study published in the journal Ambio, scientists found that lead levels in soil in the Northeastern United States had decreased markedly since the introduction of unleaded gasoline. Many scientists had believed that the lead would stay in soil and snow for a longer period. The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected. Scientists say both studies demonstrate that certain parts of the ecosystem (生态系统) respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute. The authors of the Ambio study have found that（）A、forests get rid of lead pollution faster than expectedB、lead accumulations in forests are more difficult to deal withC、lead deposits are widely distributed in the forests of the USD、the upper layers of soil in forests are easily polluted by lead emissions” 相关考题
考题
Which of the following statements about labor unions can be concluded based on the information in the passage?A. Labor unions reached their peak of power in the 1986's.B. It. took labor unions many years to improve conditions for workers.C. The early labor unions failed .because they were not concerned with the well-being of workers.D. The early labor unions failed because they could not agree on what they wanted to fight for.
考题
听力原文：W: Then certified checks, cashier's and cash letters of credit are "all variants of demand deposits.M: Yes, that's right.Q: Which of the following is not one form. of demand deposits?(13)A．Cashier's.B．Savings certificate.C．Cash letters of credit.D．Certified cheeks.
考题
According to the text, which of the following is true?［A］ the popularity of gap years results from an increasing number of charities.［B］ Prince William was working hard during his gap year.［C］ gap years are not as fashionable as they were ten years ago.［D］ a well-structured gap year is a guarantee of university success.
考题
In the 1960s, many young Americans were dissatisfied with American society. They wanted to end the Vietnam War and to make all of the people in the U.S. equal. Some of them decided to "drop out" of American society and form their own societies . They formed utopian communities , which they called "communes," where they could follow their philosophy of "do your own thing." A group of artists founded a commune in southern Colorado called "Drop City." Following the ideas of philosopher and architect Buckminster Fuller they built domeshaped houses from pieces of old cars. Other groups, such as author Ken Kesey's Merry Pranksters, the followers fo San Francisco poet Steve Gakin, and a group that called itself the Hog Farm, lived in old school huses and traveled around the United States. The Hog Farm become famous when they helped organize the Woodstock Rock Festival in 1969. Steve Gaskin's followers tried to settle down on a farm in Tennessee, but they had to leave when some members of the gruop were arrested for growing marijuana.
Not all communes believed in the philosophy of "do you own thing," however . Twin Oaks , a commune founded in Virgiania in the late 1960s, was based on the ideas of psychologist B.F.Skinner. The people who lived at Twin Oaks were carefully controlled by Skinner's "conditioning" techniques to do things that were good for the community. In 1972, Italian architect Paolo Soleri began to build Arcosanti, a utopian city Arizsona where 2500 people will live closely together in one large building called an "archology" Soleri believes that people must live closely together so that they will all become one.
What was the Twin Oaks commune base on ? a.The philosophy of "do your own thing"
b.Virginaia in the late 1960s
c.The ideas of psychologist
d.The belief that people must live closely togerher.
考题
In the 1960s, many young Americans were dissatisfied with American society. They wanted to end the Vietnam War and to make all of the people in the U.S. equal. Some of them decided to "drop out" of American society and form their own societies . They formed utopian communities , which they called "communes," where they could follow their philosophy of "do your own thing." A group of artists founded a commune in southern Colorado called "Drop City." Following the ideas of philosopher and architect Buckminster Fuller they built domeshaped houses from pieces of old cars. Other groups, such as author Ken Kesey's Merry Pranksters, the followers fo San Francisco poet Steve Gakin, and a group that called itself the Hog Farm, lived in old school huses and traveled around the United States. The Hog Farm become famous when they helped organize the Woodstock Rock Festival in 1969. Steve Gaskin's followers tried to settle down on a farm in Tennessee, but they had to leave when some members of the gruop were arrested for growing marijuana.
Not all communes believed in the philosophy of "do you own thing," however . Twin Oaks , a commune founded in Virgiania in the late 1960s, was based on the ideas of psychologist B.F.Skinner. The people who lived at Twin Oaks were carefully controlled by Skinner's "conditioning" techniques to do things that were good for the community. In 1972, Italian architect Paolo Soleri began to build Arcosanti, a utopian city Arizsona where 2500 people will live closely together in one large building called an "archology" Soleri believes that people must live closely together so that they will all become one.
Why did some young Americans decide to "drop out" of scoiety during the 1960s?a.They were not satisfied with American society.
b.They wanted to grow marijuana.
c.They wanted to go to the Vietnam War.
d.They did not want all people to be equal.
考题
共用题干
New research from NASA scientists suggests emissions of black soot after the way sunlight re- flects off snow.According to a computer simulation,black soot may be responsible for 25 percent of observed global warming over the past century. Soot in the higher latitudes（维度）of the Earth,where ice is more common , absorbs more of the sun's energy and warmth than an icy,white background. Dark-colored black carbon,or soot, absorbs sunlight,while lighter colored ice reflects sunlight.Soot in areas with snow and ice may play an important role in climate change.Also,if snow and ice covered areas begin melting,the warming effect increase,as the soot becomes more con-centrated on the snow surface.“This provides a positive feedback,as glaciers and ice sheets melt, they tend to get even dirtier.”said Dr. James Hansen,a researcher at NASA's Goddard Institute for Space Studies,New York.Hansen found soot's effect on snow albedo（反照率）,which may be contributing to trends to-ward early springs in the Northern Hemisphere,such as thinning Arctic sea ice and melting glac-iers permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.“Black carbon reduces the amount of energy reflected by snow back into space,thus heating the snow surface more than if there were no black carbon,”Hansen said. Soot's increased absorp-tion of solar energy is especially effective in warming the world's climate.“ This forcing is unusual-ly effective,causing twice as much global warming as a carbon-dioxide forcing of the same magni-tude.”Hansen noted.Hansen cautioned,although the role of soot in altering global climate is substantial,it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century .Such gases are expected to be the largest climate forcing for the rest of the century.The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were coherent with the researchers' climate model situations,which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight. What is the main cause of climate warming during the past century?A: Soot.B: Snow.C: Greenhouse gases.D:.Wind.
考题
共用题干
New research from NASA scientists suggests emissions of black soot after the way sunlight re- flects off snow.According to a computer simulation,black soot may be responsible for 25 percent of observed global warming over the past century. Soot in the higher latitudes（维度）of the Earth,where ice is more common , absorbs more of the sun's energy and warmth than an icy,white background. Dark-colored black carbon,or soot, absorbs sunlight,while lighter colored ice reflects sunlight.Soot in areas with snow and ice may play an important role in climate change.Also,if snow and ice covered areas begin melting,the warming effect increase,as the soot becomes more con-centrated on the snow surface.“This provides a positive feedback,as glaciers and ice sheets melt, they tend to get even dirtier.”said Dr. James Hansen,a researcher at NASA's Goddard Institute for Space Studies,New York.Hansen found soot's effect on snow albedo（反照率）,which may be contributing to trends to-ward early springs in the Northern Hemisphere,such as thinning Arctic sea ice and melting glac-iers permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.“Black carbon reduces the amount of energy reflected by snow back into space,thus heating the snow surface more than if there were no black carbon,”Hansen said. Soot's increased absorp-tion of solar energy is especially effective in warming the world's climate.“ This forcing is unusual-ly effective,causing twice as much global warming as a carbon-dioxide forcing of the same magni-tude.”Hansen noted.Hansen cautioned,although the role of soot in altering global climate is substantial,it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century .Such gases are expected to be the largest climate forcing for the rest of the century.The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were coherent with the researchers' climate model situations,which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight.“This forcing” in Paragraph 5 refers to_____.A: sun's heating on snow surfaceB: soot's increased absorption of solar energyC: carbon-dioxide's warming effectD: snow's increased reflection of sunlight
考题
共用题干
New research from NASA scientists suggests emissions of black soot after the way sunlight re- flects off snow.According to a computer simulation,black soot may be responsible for 25 percent of observed global warming over the past century. Soot in the higher latitudes（维度）of the Earth,where ice is more common , absorbs more of the sun's energy and warmth than an icy,white background. Dark-colored black carbon,or soot, absorbs sunlight,while lighter colored ice reflects sunlight.Soot in areas with snow and ice may play an important role in climate change.Also,if snow and ice covered areas begin melting,the warming effect increase,as the soot becomes more con-centrated on the snow surface.“This provides a positive feedback,as glaciers and ice sheets melt, they tend to get even dirtier.”said Dr. James Hansen,a researcher at NASA's Goddard Institute for Space Studies,New York.Hansen found soot's effect on snow albedo（反照率）,which may be contributing to trends to-ward early springs in the Northern Hemisphere,such as thinning Arctic sea ice and melting glac-iers permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.“Black carbon reduces the amount of energy reflected by snow back into space,thus heating the snow surface more than if there were no black carbon,”Hansen said. Soot's increased absorp-tion of solar energy is especially effective in warming the world's climate.“ This forcing is unusual-ly effective,causing twice as much global warming as a carbon-dioxide forcing of the same magni-tude.”Hansen noted.Hansen cautioned,although the role of soot in altering global climate is substantial,it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century .Such gases are expected to be the largest climate forcing for the rest of the century.The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were coherent with the researchers' climate model situations,which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight. Which of the following statements of soot is NOT true?A: It absorbs sun's heat.B: It is responsible for climate change.C: It reflects sunlight.D:.It may account for a quarter of global warming over the past century.
考题
共用题干
New research from NASA scientists suggests emissions of black soot after the way sunlight re- flects off snow.According to a computer simulation,black soot may be responsible for 25 percent of observed global warming over the past century. Soot in the higher latitudes（维度）of the Earth,where ice is more common , absorbs more of the sun's energy and warmth than an icy,white background. Dark-colored black carbon,or soot, absorbs sunlight,while lighter colored ice reflects sunlight.Soot in areas with snow and ice may play an important role in climate change.Also,if snow and ice covered areas begin melting,the warming effect increase,as the soot becomes more con-centrated on the snow surface.“This provides a positive feedback,as glaciers and ice sheets melt, they tend to get even dirtier.”said Dr. James Hansen,a researcher at NASA's Goddard Institute for Space Studies,New York.Hansen found soot's effect on snow albedo（反照率）,which may be contributing to trends to-ward early springs in the Northern Hemisphere,such as thinning Arctic sea ice and melting glac-iers permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.“Black carbon reduces the amount of energy reflected by snow back into space,thus heating the snow surface more than if there were no black carbon,”Hansen said. Soot's increased absorp-tion of solar energy is especially effective in warming the world's climate.“ This forcing is unusual-ly effective,causing twice as much global warming as a carbon-dioxide forcing of the same magni-tude.”Hansen noted.Hansen cautioned,although the role of soot in altering global climate is substantial,it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century .Such gases are expected to be the largest climate forcing for the rest of the century.The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were coherent with the researchers' climate model situations,which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight. Which of the following areas shows a greater warming effect?A: Ice sea areas.B: Areas with black carbon.C: Areas covered with white snow.D: Melting glaciers.
考题
根据以下材料，回答
The American Revolution was not arevolution in the sense of a radical or total change. It was not a sudden andviolent overturning of the political and social framework, such as lateroccurred in France and Russia, when both were already independent nations.Significant changes were ushered in, but they were not breathtaking. Whathappened was accelerated evolution rather than outright revolution. During theconflict itself people went on working and praying, marrying and playing. Mostof them were not seriously disturbed by the actual fighting, and many of themore isolated communities scarcely knew that a war was on.
America′s War of Independence heralded thebirth of three modem nations. One was Canada, which received its first largeinflux of English-speaking population from the thousands of loyalists who fledthere from the United States. Another was Australia, which became a penalcolony now that America was no longer available for prisoners and debtors. Thethird new comer--the United States--based itself squarely on republican principles.
Yet even the political overturn was not asrevolutionary as one might suppose. In some states, notable Connecticut andRhode Island, the war largely ratified a colonial self-rule alreadyexisting.British officials, everywhere ousted, were replaced by a home-growngoverning class, which promptly sought a local substitute for king andParliament.
Which of the following would be thebest title for the passage?A.The United States: An Isolated Community
B.Surprising Events During the AmericanRevolution
C.Canada and the American War ofIndependence
D.The American Revolution: Evolution NotRevolution
考题
根据以下材料，回答
The American Revolution was not arevolution in the sense of a radical or total change. It was not a sudden andviolent overturning of the political and social framework, such as lateroccurred in France and Russia, when both were already independent nations.Significant changes were ushered in, but they were not breathtaking. Whathappened was accelerated evolution rather than outright revolution. During theconflict itself people went on working and praying, marrying and playing. Mostof them were not seriously disturbed by the actual fighting, and many of themore isolated communities scarcely knew that a war was on.
America′s War of Independence heralded thebirth of three modem nations. One was Canada, which received its first largeinflux of English-speaking population from the thousands of loyalists who fledthere from the United States. Another was Australia, which became a penalcolony now that America was no longer available for prisoners and debtors. Thethird new comer--the United States--based itself squarely on republican principles.
Yet even the political overturn was not asrevolutionary as one might suppose. In some states, notable Connecticut andRhode Island, the war largely ratified a colonial self-rule alreadyexisting.British officials, everywhere ousted, were replaced by a home-growngoverning class, which promptly sought a local substitute for king andParliament.
What will the paragraph following thepassage most probably discuss?A.The transport of prisoners to Australia.
B.The creation of new state governments.
C.Events leading up to the AmericanRevolution.
D.How Canada and the United States becamefriends.
考题
Questions 21 to 25 are based on the following passage.
Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation worldwide has decreased significantly.
A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining.
In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States.
In a study published in the journal Ambio, scientists found that lead levels in soil in the Northeastern United States had decreased markedly since the introduction of unleaded gasoline.
Many scientists had believed that the lead would stay in soil and snow for a longer period.
The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected.
Scientists say both studies demonstrate that certain parts of the ecosystem (生态系统) respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute.
It can be inferred from the last paragraph that scientists （）A、are puzzled by the mystery of forest pollutionB、feel relieved by the use of unleaded gasolineC、still consider lead pollution a problemD、lack sufficient means to combat lead pollution
考题
Questions 21 to 25 are based on the following passage.
Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation worldwide has decreased significantly.
A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining.
In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States.
In a study published in the journal Ambio, scientists found that lead levels in soil in the Northeastern United States had decreased markedly since the introduction of unleaded gasoline.
Many scientists had believed that the lead would stay in soil and snow for a longer period.
The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected.
Scientists say both studies demonstrate that certain parts of the ecosystem (生态系统) respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute.
The study published in the journal Nature indicates that （）A、the Clean Air Act has not produced the desired resultsB、lead deposits in arctic snow are on the increaseC、lead will stay in soil and snow longer than expectedD、the US is the major source of lead pollution in arctic snow
考题
The economy of the United states after 1952 was the econnomy of a well-fed,almost fully employed people. Despit occasional alarms, the country escaped any postwar depression and lived in a state of boom. A n economic survey of the year 1955, a typical year of the 1950’s, may be typical as illustrating the rapid economic growth of the decade. The national output was value at 10 percent above that of 1954 (1955 output was estimated at 392 billion dollars). The production of manufacturers was about 40 percent more than it had averaged in the years immediately following World War 2. The country’s business spent about 30billion dollars for new factories and machinery. National income available for spending was almost a third greater than it had been it had been in 1950. Consumers spent about 256 billion dollars; that is about 700 million dollars a day ,or about twenty-five million dollars every hour , all round the clock. Sixty-five million people held jobs and only a little more than two million wanted jobs but could not find them . Only agriculture complained that it was not sharing in the room. To some observers this was an ominous echo of the mid-1920’s . As farmer’s shre of their products declined , marketing costs rose. But there were , among the observers of the national economy, a few who were not as confident as the majority . Those few seemed to fear that the boom could not last and would eventually lead to the oppsite-depression.
Which of the following were LEAST satisfied with the national economy in the 1950’s?（）A、EconomistsB、FrmaersC、PoliticiansD、Steelworkers
考题
Questions 21 to 25 are based on the following passage.
Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation worldwide has decreased significantly.
A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining.
In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States.
In a study published in the journal Ambio, scientists found that lead levels in soil in the Northeastern United States had decreased markedly since the introduction of unleaded gasoline.
Many scientists had believed that the lead would stay in soil and snow for a longer period.
The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected.
Scientists say both studies demonstrate that certain parts of the ecosystem (生态系统) respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute.
How did scientists discover the source of lead pollution in Greenland? （）A、By analyzing the data published in journals like Nature and Ambio.B、By observing the lead accumulations in different parts of the arctic area.C、By studying the chemical elements of soil and snow in Northeastern America.D、By comparing the chemical compositions of leaded gasoline used in various countries.
考题
Questions 21 to 25 are based on the following passage.
Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation worldwide has decreased significantly.
A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining.
In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States.
In a study published in the journal Ambio, scientists found that lead levels in soil in the Northeastern United States had decreased markedly since the introduction of unleaded gasoline.
Many scientists had believed that the lead would stay in soil and snow for a longer period.
The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected.
Scientists say both studies demonstrate that certain parts of the ecosystem (生态系统) respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute.
Lead accumulation worldwide decreased significantly after the use of unleaded gas in the US （）A、was discouragedB、was enforced by lawC、was prohibited by lawD、was introduced
考题
单选题According to the passage, a major difference between the colonization policy of the United States and that of Mexico in Texas in the 1800’s was the _____.A
degree to which policies were based on traditionB
form of economic interdependency between different cultural groupsC
treatment of the native inhabitantsD
relationship between the military and the settlers
考题
单选题Which of the following is TRUE?A
In the 1920s, women were limited to being teachers, nurses or office workers.B
Women mainly paid their attention to how they were paid in the 1960s.C
Women asked to change “all men are created equal” into “all human beings are created equal”.D
No states have ever provided women with jobs in the government.
考题
单选题According to the passage, which of the following is TRUE?A
Freedman and his colleagues hired 400,000 Americans to collect data.B
About four hundred thousand Americans worked for Freedman's team full time for 13 years.C
People who took part in Freedman's research are about 50 to 70 years old.D
People who are 50 to 70 years old seldom drink coffee
考题
单选题The modern Internet, first established in the mid-1980s, is based on the technology developed for the ARPANET, it was created by the United States Department of Defense in the 1960s.A
ARPANET, it was created by the United States Department of DefenseB
ARPANET; it was created by the United States Department of DefenseC
ARPANET, which was created by the United States Department of DefenseD
ARPANET, being created by the United States Department of DefenseE
ARPANET; the United States Department of Defense created it
考题
单选题The expression “fared best” in the sentence “During the 1960s and 1970s, and again after 1992, the poorest groups fared best.” in para. 8 can be paraphrased by which of the following?A
obtained higher incomeB
lived a better lifeC
enjoyed more equalityD
paid lower income tax
考题
单选题For many years marine centrifuges were designed for （） operation, that is the machines were run for a period during which solids accumulated in the bowlThe machine was stopped when the accumulated solids began to impair its performance.A
purifyingB
batchC
long periodD
temporary
考题
单选题Questions 21 to 25 are based on the following passage.
Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation worldwide has decreased significantly.
A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining.
In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States.
In a study published in the journal Ambio, scientists found that lead levels in soil in the Northeastern United States had decreased markedly since the introduction of unleaded gasoline.
Many scientists had believed that the lead would stay in soil and snow for a longer period.
The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected.
Scientists say both studies demonstrate that certain parts of the ecosystem (生态系统) respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute.
The authors of the Ambio study have found that（）A
forests get rid of lead pollution faster than expectedB
lead accumulations in forests are more difficult to deal withC
lead deposits are widely distributed in the forests of the USD
the upper layers of soil in forests are easily polluted by lead emissions
考题
单选题NEWS BROADCAST 4 Questions 8 and 9 are based on the following news. At the end of the news item, you will be given 20 seconds to answer the questions. Now listen to the news. Top officials of several U. S. intelligence agencies believe thatA
the country’s security is not good enough.B
the U. S. will face an attempted terrorist threat.C
there will be no actual attack in the U.S.D
an anti-terrorism practice will be held in the following months.
考题
单选题NEWS BROADCAST 5 Questions 7 and 8 are based on the following news. At the end of the news item. you will be given 20 seconds to answer the questions. Now listen to the news.Which manufacturer’s sales dropped the most in percentage in June?A
Chrysler.B
Daimler Chrysler.C
General Motors.D
Ford.
考题
单选题Questions 21 to 25 are based on the following passage.
Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation worldwide has decreased significantly.
A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining.
In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States.
In a study published in the journal Ambio, scientists found that lead levels in soil in the Northeastern United States had decreased markedly since the introduction of unleaded gasoline.
Many scientists had believed that the lead would stay in soil and snow for a longer period.
The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected.
Scientists say both studies demonstrate that certain parts of the ecosystem (生态系统) respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute.
The study published in the journal Nature indicates that （）A
the Clean Air Act has not produced the desired resultsB
lead deposits in arctic snow are on the increaseC
lead will stay in soil and snow longer than expectedD
the US is the major source of lead pollution in arctic snow
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