1、大学英语六级 110 及答案解析(总分：428.04，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 thirty minutes to write a composition on the topic My View on Job-Hopping. You should write at least 120 words and you should base your composition on the outline (given in Chinese) below: 1有些人
2、喜欢始终从事一种工作，因为 2有些人喜欢经常更换工作，因为 3我的看法。 （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 whi
3、ch 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 Hartu
4、ng 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 carri
6、ed 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 chang
7、e 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
8、chemicals 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-wel
9、fare 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
10、in 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 s
11、late 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 examp
12、le. 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 calami
13、ty 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 c
14、onceivable 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
15、doing 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 on
16、e 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
17、just 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 registere
18、d 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
19、embryotoxicity 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
20、Assessment 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 9
22、5 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
23、study 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
25、now 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 numb
26、er 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
27、completely 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 ne
29、eded 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,
30、from 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 rea
31、l 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
32、prove 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.
33、NG(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 ref
34、ined 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.She was approving.B.She was apologetic.C.She was annoyed.D.She was careless.A.A visitor has borrowed i
36、t.B.She had given it to her guide.C.A friend took it to the West.D.Bill gave it back to his friend.A.She agrees with the man.B.She hasnt seen Kevin recently.C.She thinks Kevin will be late.D.She doesnt know what the man means.A.Anthony fixed it.B.The plumber fixed it.C.It was left leaking.D.It was r
37、emoved.A.In a clothing store.B.In a garden.C.At a cleaners.D.At a printing shop.A.Being too hot.B.Being delayed.C.Catching the beach ball.D.Getting up early.A.It looks better than the other one.B.The man needs more wall space for it.C.It should be put on another wall.D.It makes the wall a little mor
38、e attractive.A.The experiment will take a long time.B.The students should count their time in the lab.C.Dr. Walters teaches biology in the afternoon.D.Biology lab is open one hour every afternoon.四、Section A(总题数：2，分数：10.00)A.Places the man has visited.B.A paper the woman is writing for a class.C.Sch
39、ool activities they enjoy.D.The womans plans for the summer.A.She has never been to Gettysburg.B.She took a political science course.C.Her family still goes on vacation together.D.Shes interested in the United States Civil War.A.Why her parents wanted to go to Gettysburg.B.Why her familys vacation p
40、lan changed ten years ago.C.Where her family went for a vacation ten years ago.D.When her family went on their last vacation.A.Its only open to poetry majors.B.It requires another course first.C.Its already full.D.Its only offered in the morning.A.The class meets during his working hours.B.The class
41、 is too far away.C.He has another class at the same time.D.Hes already familiar with the material.A.Its courses cost less.B.It has a pool.C.The class size is smaller.D.It may offer the course he needs during the day.五、Section B(总题数：3，分数：10.00)A.Because there werent any professional teams in the U.S.
42、 then.B.Because Pele hadnt retired from the Brazilian National Team yet.C.Because this fast-moving sport wasnt familiar to many Americans.D.Because good professional players received low salaries.A.When it has a large number of fans.B.When it plays at home.C.When it has many international stars play
43、ing for it.D.When the fans cheer enthusiastically for it.A.It wasnt among the top four teams.B.It didnt play as well as expected.C.It won the World Cup.D.It placed fourth.A.The coffee market in Boston.B.The role of supermarkets in the coffee business.C.A new trend in the United States.D.The advertis
44、ing of a new product.A.Gourmet coffee is less expensive.B.Regular brands of coffee have too much caffeine.C.Gourmet coffee tastes better.D.Gourmet coffee is grown in the United States.A.They will run out of coffee.B.They will successfully compete with gourmet coffee sellers.C.They will introduce new
45、 regular brands of coffee.D.They will lose some coffee business.A.They will be much bigger.B.They will have more seats.C.They will have three wheels.D.They will need intelligent drivers.A.It doesnt need to be refueled.B.It will use solar energy as fuel.C.It will be driven by electrical power.D.It wi
46、ll be more suitable for long distance travel.A.Passengers in the car may be seated facing one another.B.The front seats will face forward and the back seats backward.C.Special seats will be designed .for children.D.More seats will be added.A.Choose the right route.B.Refuel the car regularly.C.Start
47、the engine.D.Tell the computer where to go.六、Section C(总题数：1，分数：10.00)Im sure almost every one of you looked at your watch or at a clock before you came to class today. Watches and (36) 1seem as much a part of our life as breathing or eating. And yet, did you know that watches and were (37) 2in the United States until the 1850s? In the late 1700s, people didnt know the (38) 3time unless they were near a clock. Those (39) 4 in the squares of European towns
