[外语类试卷]大学英语四级模拟试卷105及答案与解析.doc
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1、大学英语四级模拟试卷 105及答案与解析 一、 Part I Writing (30 minutes) 1 1社会习惯的不同普遍存在; 2美国和中国习惯的不同之处; 3我们的做法。 Different Social Customs Between Americans and Chinese 二、 Part II Reading Comprehension (Skimming and Scanning) (15 minutes) Directions: In this part, you will have 15 minutes to go over the passage quickly an
2、d answer the questions attached to the passage. For questions 1-7, mark: Y (for YES) if the statement agrees with the information given in the passage; N (for NO) if the statement contradicts the information given in the passage; NG (for NOT GIVEN) if the information is not given in the passage. 2 T
3、esting Times Researchers are working on ways to reduce the need for animal experiments, but new laws may increase the number of experiments needed. The current situation In an ideal world, people would not perform experiments on animals. For the people, they are expensive. For the animals, they are
4、stressful and often painful. That ideal world, sadly, is still some way away. People need new drugs and vaccines. They want protection from the toxicity of chemicals. The search for basic scientific answers goes on. Indeed, the European Commission is forging ahead with proposals that will increase t
5、he number of animal experiments carried out in the European Union, by requiring toxicity tests on every chemical approved for use within the unions borders in the past 25 years. Already, the commission has identified 140,000 chemicals that have not yet been tested. It wants 30,000 of these to be exa
6、mined right away, and plans to spend between 4 billion 8 billion ($5 billion 10 billion) doing so. The number of animals used for toxicity testing in Europe will thus, experts reckon, quintuple (翻五倍 ) from just over lm a year to about 5m, unless they are saved by some dramatic advances in non-animal
7、 testing technology. At the moment, roughly 10% of European animal tests are for general toxicity, 35% for basic research, 45% for drugs and vaccines, and the remaining 10% a variety of uses such as diagnosing diseases. Animal experimentation will therefore be around for some time yet. But the searc
8、h for substitutes continues, and last weekend the Middle European Society for Alternative Methods to Animal Testing met in Linz, Austria, to review progress. A good place to start finding alternatives for toxicity tests is the liver-the organ responsible for breaking toxic chemicals down into safer
9、molecules that can then be excreted. Two firms, one large and one small, told the meeting how they were using human liver cells removed incidentally during surgery to test various substances for long-term toxic effects. One way out of the problem PrimeCyte, the small firm, grows its cells in culture
10、s over a few weeks and doses them regularly with the substance under investigation. The characteristics of the cells are carefully monitored, to look for changes in their microanatomy. Pfizer, the big firm, also doses its cultures regularly, but rather than studying individual cells in detail, it co
11、unts cell numbers. If the number of cells in a culture changes after a sample is added, that suggests the chemical in question is bad for the liver. In principle, these techniques could be applied to any chemical. In practice, drugs (and, in the case of PrimeCyte, food supplements) are top of the li
12、st. But that might change if the commission has its way: those 140,000 screenings look like a lucrative market, although nobody knows whether the new tests will be ready for use by 2009, when the commission proposes that testing should start. Other tissues, too, can be tested independently of animal
13、s. Epithelix, a small firm in Geneva, has developed an artificial version of the lining of the lungs. According to Huang Song, one of Epithelixs researchers, the firms cultured cells have similar microanatomy to those found in natural lung linings, and respond in the same way to various chemical mes
14、sengers. Dr. Huang says that they could be used in long-term toxicity tests of airborne chemicals and could also help identify treatments for lung diseases. The immune system can be mimicked and tested, too. ProBioGen, a company based in Berlin, is developing an artificial human lymph node (淋巴结 ) wh
15、ich, it reckons, could have prevented the neardisastrous consequences of a drag trial held in Britain three months ago, in which (despite the drag having passed animal tests) six men suffered multiple organ failure and nearly died. The drug the men were given made their immune systems hyperactive. S
16、uch a response would, the firms scientists reckon, nave teen identified by their lymph node, which is made from cells that provoke the immune system into a response. ProBioGens lymph node could thus work better than animal testing. A second alternative Another way of cutting the number of animal exp
17、eriments would be to change the way that vaccines are tested, according to Coenraad Hendriksen of the Netherlands Vaccine Institute. At the moment, all batches of vaccine are subject to the same battery of tests. Dr. Hendriksen argues that this is over-rigorous. When new vaccine cultures are made, b
18、elt-and-braces tests obviously need to be applied. But if a batch of vaccine is derived from an existing culture, he suggests that it need be tested only to make sure it is identical to the batch from which it is derived. That would require fewer test animals. All this suggests that though there is
19、still some way to go before drugs, vaccines and other substances can be tested routinely on cells rather than live animals, useful progress is being made. What is harder to see is how the use of animals might be banished from fundamental research. Weighing the balance In basic scientific research, w
20、here the object is to understand how, say, the brain works rather than to develop a drug to treat brain disease, the whole animal is often necessarily the object of study. Indeed, in some cases, scientific advances are making animal tests more valuable, rather than less. Geneticmodification techniqu
21、es mean that mice and rats can be remodelled to make them exhibit illnesses that they would not normally suffer from. Also, genes for human proteins can be added to them, so that animal tests will more closely mimic human responses. This offers the opportunity to understand human diseases better, an
22、d to screen treatments before human trials begin. However, the very creation of these mutants (突变异种 ) counts as an animal experiment in its own right, so the number of experiments is increasing once again. What is bad news for rodents, though, could be good news for primates. Apes and monkeys belong
23、 to the same group of mammals as humans, and are thus seen as the best subjects for certain sorts of experiment. To the extent that rodents can be “humanised“, the number of primate experiments might be reduced. Some people, of course, would like to see them eliminated altogether, regardless of the
24、effect on useful research. On June 6th the British Union for the Abolition of Vivisection, an animal-rights group, called for the use of primates in research to be banned. For great apes, this has already happened. Britain, Austria, the Netherlands, New Zealand and Sweden have ended experiments on c
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