[外语类试卷]大学英语六级模拟试卷96及答案与解析.doc

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1、大学英语六级模拟试卷 96及答案与解析 一、 Part I Writing (30 minutes) 1 For this part, you are allowed 30 minutes to write a composition on the topic Economic Development and Moral Decline. You should write at least 150 words and you should base your composition on the outline (given in Chinese) be low: 1. 近年来我国经济建设取得

2、了很大成就 ; 2. 但与此同时 ,社会风气随着经济的发展也日益下降 3. 我的观点 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 and answer the questions attached to the passage. For questions 1-4, mark： Y (for YES) if the statement a

3、grees 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 GENETICALLY MODIFIED FOODS Are genetically modified crops an environmental dream come-true or a disaster

4、 in the making? Scientists are looking for answers. The world seems increasingly divided into those who favor genetically modified(GM) foods and those who fear them Advocates assert that growing genetically altered crops can be kinder to the environment and that eating foods from those plants is per

5、fectly safe. And, they say genetic engineering which can induce plants to grow in poor soils or to produce more nutritious foods will soon become an essential tool for helping to feed the worlds burgeoning population. Skeptics contend that GM crops could pose unique risks to the environment and to h

6、ealth risks too troubling to accept placidly, Taking that view, many European countries are restricting the planting and importation of GM agricultural products. Much of the debate hinges on perceptions of safety. But what exactly does recent scientific research say about the hazards? The answers, t

7、oo often lost in reports on the controversy, are served up in the pages that follow. Two years ago in Edinburgh, Scotland, eco-vandals stormed a field, crushing canola plants. Last year in Maine, midnight raiders hacked down more than 3000 experimental poplar trees. And in Sun Diego, protesters smas

8、hed sorghum and sprayed paint over greenhouse walls. This far-flung outrage took aim at genetically modified crops. But the protests backfired: all the destroyed plants were conventionally bred. In each case, activists mistook ordinary plants for GM varieties. Its easy to understand why. In a way, G

9、M crops now on some 109 million acres of farmland worldwide are invisible. You cant see, taste or touch a gene inserted into a plant or sense its effects on the environment. You cant tell, just by looking, whether pollen containing a foreign gene can poison butterflies or fertilize plants miles away

10、. That invisibility is precisely what worries people. How, exactly, will GM crops affect the environment and when will we notice? Advocates of GM, or transgenic, crops say the plants will benefit the environment by requiting fewer toxic pesticides than conventional crops. But critics fear the potent

11、ial risks and wonder how big the benefits really are. “We have so many questions about these plants,“ remarks Guenther Stotzky, a soil microbiologist at New York University. “Theres a lot we dont know and need to find out.“ As GM crops multiply in the landscape, unprecedented numbers of researchers

12、have started fanning into the fields to get the missing information. Some of their recent findings are reassuring; others suggest a need for vigilance. Fewer Poisons in the Soil? Every year U.S. growers shower crops with an estimated 971 million pounds of pesticides, mostly to kill insects, weeds an

13、d fungi. But pesticide residues linger on crops and the surrounding soil, leaching into groundwater, running into streams and getting gobbled up by wildlife. The constant chemical trickle is an old worry for environmentalists. In the mid-1990s agribusinesses began advertising GM seeds that promised

14、to reduce a farmers use of toxic pesticides. Today most GM crops-mainly soybean, com, cotton and canola-contain genes enabling them to either resist insect pests or tolerate weed-killing herbicides. The insect-resistant varieties make their own insecticide, a property meant to reduce the need for ch

15、emical sprays. The herbicidetolerant types survive when exposed to broad-spectrum weed killers, potentially allowing farmers to forgo more poisonous chemicals that target specific weed species. Farmers to limit the use of more hazardous pesticides when they can, but GM crops also hold appeal because

16、 they simplify operations (reducing the frequency and complexity of pesticide applications) and, in some cases, increase yields. But confirming environmental benefit is tricky. Virtually no peer-reviewed papers have addressed such advantages, which would be expected to vary from plant to plant and p

17、lace to place. Some information is available, however. According to the U.S. Department of Agriculture, farmers who plant herbicidetolerant crops do not necessarily use fewer sprays, but they do apply a more benign mix of chemicals. For instance, those who grow herbicide-tolerant soybeans typically

18、avoid the most noxious weed killer, turning instead to glyphosate herbicides(苷磷除草剂 ), which are less to toxic and degrade more quickly. Insect-resistant crops also bring mixed benefits. To date. insect resistance has been provided by a gene from the soil bacterium Bacillus thuringiensis(Bt)(杆菌苏立菌 )

19、This gene directs cells to manufacture a Crystalline protein that is toxic to certain insectsespecially caterpillars and beetles that gnaw on crops but does not harm other organisms. The toxin gene m different strains of B. thuringiensis can affect different mixes of insects, so seed makers can sele

20、ct the version that seems best suited to a particular crop. Of all the crops carrying Bt genes, cotton has brought the biggest drop in pesticide use. According to the Environmental Protection Agency, in 1999 growers in states using high amounts of Bt cotton sprayed 21 percent less insecticide than u

21、sual on the crop. Thats a “dramatic and impressive“ reduction, says Stephen Johnson, an administrator in the EPAs Office of Pesticide Programs. Typically, Johnson says, a farmer might spray insecticides on a cotton field 7 to 14 times during a single growing season. “If you choose a Bt cotton produc

22、t, you may have little or no use for these pretty harsh chemicals,“ he notes. Growers of Bt com and potatoes report less of a pesticide reduction, partly because those plants normally require fewer pesticides and face fluctuating numbers of pests. Defining the environmental risks of GM crops seems e

23、ven harder than calculating their benefits. At the moment, public attention is most trained on Bt crops, thanks to several negative studies. Regulators, too, are surveying the risks intensely. This spring or summer the EPA is expected to issue major new guidelines for Bt crops, ordering seed produce

24、rs to show more thoroughly that the crops can be planted safely and monitored in farm fields. At What Cost to Wildlife? In 1998 a Swiss study provoked widespread worry that Bt plants can inadvertently harm unlucky creatures. In this laboratory experiment, green lacewing(草蛉 ) caterpillars proved more

25、 likely to die after eating European corn-borer caterpillars that had fed on Bt com instead of regular corn. The flames of fear erupted again a year later, when Cornell University entomologist John Losey and his colleagues reported that riley had fed milkweed (乳草属植物 ) leaves dusted with Bt corn poll

26、en to monarch butterfly larvae in the lab and that those larvae, too, had died. “That was the straw that broke the camels back.“ says David Pimentel, also an entomologist at Cornell. Suddenly, all eyes turned to the organisms munching GM plant leaves, nipping modified pollen or wriggling around in t

27、he soil below the plants-organisms that play vital roles in sustaining plant populations. Another alarming study relating to monarch but-terries appeared last August. But the lab bench is not a farm field, and many scientists question the usefulness of these early experiments. The lab insects, they

28、note, consumed far higher doses of Bt toxin than they would outside, in the real world. So researchers have headed into nature themselves, measuring the toxin in pollen from plots of GM com, estimating how much of it drifts onto plants such as milkweed and, finally, determining the exposure of butte

29、rfly and moth larvae to the protein. Much of that work, done during the 2000 growing season, is slated to be reported to the EPA shortly. According to the agency, however, preliminary studies evaluating the two most common Bt corn plants (from Novartis and Monsanto) already indicate that monarch lar

30、vae encounter Bt corn pollen on milkweed plants but at levels too low to be toxic. What is toxic? The EPA estimates that the insects face no observable harm when consuming milkweed leaves laden with up to 150 corn pollen grains per square centimeter of leaf surface. Recent studies of milkweed plants

31、 in and around the cornfields of Maryland, Nebraska and Ontario report far lower levels of Bt pollen, ranging from just 6 to 78 grains of Bt corn pollen per square centimeter of milkweed leaf surface. “The weight of the evidence suggests Bt corn pollen in the field does not pose a hazard to monarch

32、larvae,“ concludes EPA scientist Zigfridas Vaituzis, who heads the agencys team studying the ecological effects of Bt crops. But the jury is still out. “Theres not much evidence to weigh.“ notes Jane Rissler of the Union of Concerned Scientists. “This issue of nontarget effects is just a black hole.

33、 and EPA has very little good data at this point to conclude whether the monarch butterfly problem is real, particularly in the long term.“ In an EPA meeting on GM crops last fall. Vaituzis acknowledged the lack of long-term data on Bt crops and insect populations. Such studies “require more time th

34、an has been available since the registration of Bt crops,“ Vaituzis remarked. The EPA, he added, continues to collect Bt crop data but so far without evidence of “unreasonable adverse effects“ on insects in the field. 2 Many experts who favor genetically modified foods believe that genetic engineeri

35、ng can help to meet the demands of the worlds increasing population. （ A） Y （ B） N （ C） NG 3 Some European countries are restricting the planting and importation of GM agricultural products because GM crops could pose unique risks to the environment and to health. （ A） Y （ B） N （ C） NG 4 Rice is one

36、 of the major GM crops containing genes which help to either resist insect or tolerate weed-killing herbicides. （ A） Y （ B） N （ C） NG 5 Study done in Swiss and Cornell University indicated that Bt crops could have unreasonable adverse effects on insects in the field. （ A） Y （ B） N （ C） NG 6 To certa

37、in extent, GM crops are regarded as _ since the gene inserted into a plant cannot be seen, tasted or touched. 7 The two factors contributing to the appealing of GM crops to farmers are and _. 8 The plants would be insect resistant as a gene from the soil bacterium could direct cells to produce _ tha

38、t is toxic to certain insects. 9 Among all the GM crops, Bt genes have proved most effective in _ when the largest reduction in pesticide use has been reported. 10 It is much more difficult to _ than to calculate the benefits of the GM crops. 11 Researches in the wild field evaluating the two most c

39、ommon Bt corn plants showed that the toxin absorbed was too _. Section A Directions: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will b

40、e spoken only once. After each question there will be a pause. During the pause, you must read the four choices marked A, B, C and D, and decide which is the best answer. （ A） His paycheck is late. （ B） The book bag is too expensive. （ C） He cant lend the woman any money. （ D） The woman doesnt need

41、a new book bag. （ A） Both games are played worldwide. （ B） Chess is more difficult. （ C） Both games can be learnt by children. （ D） He cant compare the two games. （ A） Monday morning. （ B） Monday afternoon. （ C） Wednesday morning. （ D） Friday afternoon. （ A） The woman should return his tape player b

42、y Friday. （ B） The woman should buy him a new tape player. （ C） By Friday he should be able to borrow a tape player. （ D） He cant wait until Friday for his tape player. （ A） He doesnt go on a diet recently. （ B） He usually takes his weight to work. （ C） He has put on much weight. （ D） He eats chocol

43、ate time and again. （ A） They have to buy some umbrellas. （ B） They should go back and get the umbrella. （ C） They should stop traveling. （ D） They can go on traveling. （ A） He cant see very well. （ B） Hes not feeling well. （ C） His eye doesnt hurt very much. （ D） His eye isnt healing very quickly.

44、（ A） Customer and clerk. （ B） Professor and student. （ C） Boss and employee. （ D） Lawyer and client. （ A） Why KTV is popular in China. （ B） How the employees spend their weekend usually. （ C） Where to celebrate their success. （ D） Which is the best pub in the neighborhood. （ A） Eric comes from Europ

45、e, while Chen is a Chinese. （ B） Chen suggests that they go to pubs. （ C） Chen already knows that Eric has no interest in KTV. （ D） Some of the employees in the company are Americans. （ A） Eric takes Chens advice at the end of the dialogue. （ B） Eric seldom goes to KTV. （ C） Most Americans prefer to

46、 go out to sing with their friends. （ D） Chinese people do not like to go to pubs. （ A） At a newspaper. （ B） At an advertising agency. （ C） At a furniture store. （ D） At a real estate office. （ A） A two-bedroom apartment. （ B） A sofa. （ C） A chair. （ D） A roommate. （ A） Her phone number. （ B） The lo

47、cation of the apartment. （ C） The best time to call her. （ D） Her first name. （ A） $5. （ B） $15. （ C） $30. （ D） $250. Section B Directions: In this section, you will hear 3 short passages. At the end of each passage, you will hear some questions. Both the passage and the questions will be spoken onl

48、y once. After you hear a question, you must choose the best answer from the four choices marked A, B, C and D. （ A） By bike. （ B） By car. （ C） By bus. （ D） On foot. （ A） She was fond of fish. （ B） She was keen on fishing. （ C） She was good at fishing. （ D） She didnt want to be left alone every Sunda

49、y. （ A） Nothing. （ B） Six big fish. （ C） An old shoe. （ D） The fish for lunch that was delicious. （ A） The care and proper selection of dogs for family pets. （ B） Different breeds of dogs. （ C） Responsibility for seeing that dogs are properly cared for. （ D） Different kinds of books about dogs. （ A） Children. （ B） Family. （ C） Parents. （ D） ASPCA （ A） They are big and aggressive. （ B） They provide companionship as well as protection. （ C） Most people are afraid of them. （ D） They are easy to