1、大学英语六级 152及答案解析(总分：447.97，做题时间：132 分钟)一、Part I Writing (3(总题数：1，分数：30.00)1.For this part, you are allowed 30 minutes to write a short essay entitled Students Union, Associations and Personal Development. You should write at least 150 words following the outline given below. 1大学里学生会和各种社团的现状 2参加学生会和各种
2、社团对个人发展的作用 3我的观念中大学生对待学生会和社团活动的正确态度 （分数：30.00）_二、Part II Reading C(总题数：1，分数：71.00)Animal tests More than a cosmetic (化妆品) change Every time you reach for an eye-drop or reapply a lip salve, you do be so confident that the chemicals they contain are safe to use. But the toxicology (毒物学) tests on whic
3、h regulators rely to gather this information are largely based on wasteful and often poorly predictive animal experiments. Efforts in Europe are about to change this, and the man charged with bringing toxicology into the twenty-first century is a plain-talking German: Thomas Hartung. Although Hartun
4、g acknowledges the immense challenges ahead, he sees this as an opportunity for toxicology “to turn itself at last into a respectable science“. Three years ago, when Hartung became director of the European Centre for the Validation of Alternative Methods (ECVAM) in Ispra, Italy. ECVAM was set up in
5、1993 to support European Union policy aimed at reducing the number of animals used in regulatory testing. The centre, which sits on the sleepy shores of Lake Maggiore in the Italian Alps, originally had ten members of staff and faced an uphill struggle to cut back the millions of animal tests carrie
6、d out in Europe every year. Then in 2003, two major policy changes were announced from above, increasing the pressure on the centres labs. ECVAM found itself facing an unexpectedly short deadline for delivering a slew of animal-free methods for testing chemical toxicity. Rule change The first change
7、 was to the European Unions Cosmetics Directive, which phases out over ten years the use of animals in cosmetics testing. A short while later, the European Commission proposed its controversial REACH legislation (Registration, Evaluation and Authorization of Chemicals). Europe produces some 30,000 c
8、hemicals for which toxicity data have never been registered. REACH aims to make registration mandatory for both future and existing chemicals even those that have been on the market for decades. If, as expected, the REACH directive is approved next year, it will come into effect in 2007. Animal-welf
9、are groups fear that this will mean millions more animals will be used in tests to meet the regulatory requirements. And industry claims that the testing process could cost billions of euros. Almost overnight, industrys interest in cheaper, animal-free testing skyrocketed. Last month ECVAM was put i
10、n charge of developing, with industry and regulatory agencies, the testing strategies for REACH. Now commanding 50 staff, Hartung is rising to the challenge. “The toxicity tests that have been used for decades are simply bad science“, he explains. “We now have an opportunity to start with a clean sl
11、ate and develop evidence-based tests that have true predictive value.“ Many of the animal tests used today were developed under crisis conditions. The notorious Draize test, which assesses the irritation or damage caused by chemicals simply by putting them into the eyes of rabbits, is a prime exampl
12、e. It was developed by the US Food and Drug Administration in 1944 after reports in the 1930s that some cosmetics were causing permanent eye injuries. One 38-year-old woman had gone blind after dyeing her lashes with Lash-Lure, a product that contained a derivative of coal tar. Then came the calamit
13、y of thalidomide (镇静剂), which was given to pregnant women in the late 1950s to control morning sickness, but which caused horrific birth defects. By this time, governments were highly sensitive to public concerns and called on their authorities to develop animal-based tests that would predict all co
14、nceivable toxic effects of drugs and chemicals. The principles behind most of those tests remain more or less unchanged today. Safety catch Each chemical that goes through the multiple tests required for registration can use up to 5,000 animals or 12,000 if the chemical is a pesticide. The cost of d
15、oing this for the 30,000 unregistered chemicals so that they comply with REACH has been estimated at between 5 billion (US$6 billion) and 10 billion. In the decade since ECVAM was established, the number of animals used in toxicology testing has fallen slightly, although it still hovers at about one
16、 million per year. This reduction is a result of the refinement of existing tests, and the introduction of some alternative methods that rely on in vitro (试管) tests using cell cultures. ECVAM believes that it can halve the total number of animals used for regulatory testing within a decade. It has j
17、ust completed its first large-scale validation study of an in vitro cytotoxicity test, which monitors death of cultured cells following short-term exposure to a chemical. Chemicals shown to be harmful in this test would be excluded from any LD50 animal tests. At least 70% of the chemicals registered
18、 in the past two decades fall into this category, says Hartung. And this is just the beginning. Poor prediction Most animal tests over-or under-estimate toxicity, or simply dont mirror toxicity in humans very well. The relevant industries also acknowledges the poor quality of those tests. Take the e
19、mbryotoxicity test in which chemicals are fed to pregnant animals and the fates of their embryos, and the progeny of two subsequent generations, are studied. “Animal embryotoxicity tests are not reliably predictive for humans,“ says Horst Spielmann, a toxicologist at the Federal Institute for Risk A
20、ssessment in Berlin. “When we find that cortisone is embryotoxic in all species tested except human, what are we supposed to make of them?“ The same goes for cancer. To test a single chemical for its potential to cause cancer takes five years and involves 400 rats, each of which is treated with the
21、maximum tolerated dose. It is dramatically over-predictive: more than 50% of the results are positive, of which 90% are false positive. Yet the number of compounds proved to be carcinogenic to humans is very low the International Agency for Research on Cancer in Lyons, France, has identified just 95
22、 proven and 66 probable human carcinogens (致癌物质). Life or death Scientists also cannot assume that in vitro alternatives are automatically better, says Spielmann. In 1971, a comparison of animal Draize tests in different labs revealed the test to be hopelessly non-reproducible. But Spielmanns 1995 s
23、tudy of animal-free alternatives to the Draize test showed that they were equally unreliable. Since then the in vitro tests have been standardized, and they are intrinsically more reproducible. “Although reproducibility and relevance are not the same thing,“ Spielmann cautions. Relevance requires a
24、good match between the test results and human data. At an ECVAM workshop in February, 30 industrial scientists met to develop the most effective strategy for using the alternative Draize tests, so that the false negatives and false positives of each test compensate for each other. This strategy is n
25、ow going through the crucial validation procedure, in which human data, often from occupational health databases, will be used as points of reference. ECVAM has so far seen 17 alternative tests through validation 11 use in vitro methods, another six involve refining in vivo tests to reduce the numbe
26、r of animals used. Most of the new tests assess acute toxicity, but animal use is highest when testing for the toxic effects of prolonged exposure to chemicals for long-term consequences such as cancer and reproductive toxicity. These costly procedures are harder to mimic in vitro and may never be c
27、ompletely replaced. Sounds familial This is why, apart from the 30 million it uses to support ECVAM annually, the European Commission is funding three multimillion-euro Integrated Projects. Under these, dozens of labs will collaborate for five years to tackle more difficult issues, such as allergic
28、reactions (过敏反应) or widespread toxicity resulting from chemicals entering the bloodstream. Scientists know that they are likely to find it hardest to convince regulators about alternative tests for highly emotive issues such as cancer and birth defects. More than half of all animals that will be nee
29、ded to support REACH legislation are likely to be used in reproductive toxicology testing. The 9-million Integrated Project called ReProTect has 27 labs dedicated to developing alternatives to these tests. The ReProTect consortium has broken down the human reproductive cycle into smaller elements, f
30、rom male and female fertility to implantation, to pre-and postnatal development, and is trying to develop a meaningful package of tests. “Quite correctly everyone feels uneasy about taking risks where stakes are so high and issues so emotive,“ says Hartung. “We all want to be sure that there is real
31、 evidence that alternative tests are predictive of human toxicity.“ For example, regulators know the weaknesses of the rat cancer test as well as scientists but, wanting to be safe rather than sorry, they accept it because it is believed to throw up few false negatives. They prefer to let industry p
32、rove the innocence of any compound that shows up positive. Any replacement tests will need to reassure both regulators and industry. （分数：71.00）(1).Most toxicology tests for cosmetics are often poorly predictive animal experiments.（分数：7.10）A.YB.NC.NG(2).Thomas Hartung is an Italian.（分数：7.10）A.YB.NC.N
33、G(3).European Unions Cosmetics Directive has 50 staff.（分数：7.10）A.YB.NC.NG(4).According to Hartung, the toxicity tests used for tens of years are simply bad science.（分数：7.10）A.YB.NC.NG(5).Thalidomide used in the late 1950s to control morning sickness caused_.（分数：7.10）_(6).ECVAM believes that the refi
34、ned in vitro test method can reduce by halve _used for regulatory testing within a decade.（分数：7.10）_(7).How is an embryotoxicity test carried out?（分数：7.10）_(8).From the passage we know that results of cancer tests on animals are often_.（分数：7.10）_(9).Reproducibility and relevance differ in the sense
35、that relevance requires_.（分数：7.10）_(10).Scientists think that they may find it most difficult to persuade regulators to use alternative tests for_.（分数：7.10）_三、Listening Comprehens(总题数：1，分数：15.00)A.Furnished apartments will cost more.B.The apartment can be furnished easily.C.The apartment is just wha
36、t the man is looking for.D.She can provide the man with the apartment he needs.A.Mr. Johnsons ideas are nonsense.B.He quite agrees with Mr. Johnsons views.C.Mr. Johnson is good at expressing his ideas.D.He shares the womans views on social welfare.A.Study in a quiet place.B.Improve her grades gradua
37、lly.C.Change the conditions of her dorm.D.Avoid distractions while study in her dorm.A.It has been put off.B.It has been cancelled.C.It will be held in a different place.D.It will be rescheduled to attract more participants.A.Janet loves the beautiful landscape of Australia very much.B.Janet is very
38、 much interested in architecture.C.Janet admires the Sydney Opera House very much.D.Janet thinks its a shame for anyone hot to visit Australia.A.It is based on a lot of research.B.It can be finished in a few weeks time.C.It has drawn criticism from lots of people.D.It falls short of her supervisors
39、expectations.A.Karen is very forgetful.B.He knows Karen better now.C.Karen is sure to pass the interview.D.The woman should have reminded Karen earlier.A.Ask Joe to apologize to the professor for her.B.Skip the class to prepare for the exam.C.Tell the professor shes lost her voice.D.Attend the lectu
40、re with the man.A.The man will go in for business right after high school.B.The woman is not happy with the mans decision.C.The man wants to be a business manager.D.The woman is working in a kindergarten.A.They stay closed until summer comes.B.They cater chiefly to tourists.C.They are busy all the y
41、ear round.D.They provide quality service to their customers.四、Section A(总题数：2，分数：10.00)A.Painting.B.Washing.C.Repairing.D.Petrol filling.A.He sent the ear to the garage.B.He did nothing about his car.C.He repaired the car himself.D.He sold his car to somebody else.A.She wears clothes similar to thos
42、e of his wifes.B.She wears clothes that were the same as his wifes.C.She wears clothes which were different from those of his wifes.D.She wears clothes which has nothing to do with his wife.A.He didnt recognize her and felt sorry to meet her.B.He broke the car.C.He was curious about his colleagues w
43、ispering.D.He did nothing.A.Mating habits of squid and octopus.B.The evolution of certain form of sea life.C.The study of marine shells.D.Survival skills of sea creatures.A.He didnt understand the lecture.B.He wants to borrow her notes next week.C.He needs help with a makeup exam.D.He was sick and u
44、nable to attend.A.Some sea creatures developed backbones.B.The first giant squid was captured.C.Some sea creatures shed their shells.D.Sea life became more intelligent.A.She has always believed they exist.B.She heard about them in New Zealand.C.Stories about them may be based on giant squid.D.The in
45、structor mentioned them in the lecture.五、Section B(总题数：3，分数：30.00)A.Replacing the native corn with the hybrid corn.B.Replacing the hybrid corn with the native corn.C.Replacing the new type of corn with the traditional corn.D.Replacing the traditional corn with the native corn.A.Excellent quality.B.L
46、arge productivity.C.Good flavor.D.Both A and B.A.Because their wives didnt like it.B.Because it wasnt good for cooking.C.Because their wives didnt like the flavor.D.All of the above.A.Professors.B.Reporters.C.Students.D.Policemen.A.Because they did not see the incident.B.Because the incident was rid
47、iculous.C.Because the victim did not want any help.D.Because they were reluctant to do so.A.They sat there, doing nothing.B.They wanted to help the robbers.C.They stopped the robbers.D.They called the reporters.A.False.B.True.C.Normal.D.Strange.A.Traveling in it.B.Studying its language.C.Living in it.D.All of the above.A.Their behaviours are becoming more similar to each other.B.The world is growing smaller.C.We are not longer interested in each other.D.Englishm
