大学英语四级考试仔细阅读练习.doc

大学英语四级考试仔细阅读练习

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洛基英语，中国在线英语教育领导品牌

If you want to spark a heated debate at a dinner party, bring up the topic about genetically modified foods. For many people, the concept of genetically altered, high-tech crop production raises all kinds of environmental, health, safety and ethical questions. Particularly in countries with long agrarian traditions -- and vocal green lobbies -- the idea seems against nature.
In fact, genetically modified foods are already yew much a part of our lives. A third of the corn and more than half the soybeans and cotton grown in the US last year were the product of biotechnology, according to the Department of Agriculture. More than 65 million acres of genetically modified crops will be planted in the US this year. The genetic is out of the bottle.
Yet there are clearly some very real issues that, need to be resolved, lake any new product entering the food chain, genetically modified foods must be subjected to rigorous testing. In wealthy count, des, the debate about biotech is tempered by the fact that we have a rich array of foods to choose from -- and a supply that far exceeds our needs. In developing countries desperate to feed fastgrowing and underfed populations; the issue is simpler and much more urgent: Do the benefits of biotech outweigh the risks?
The statistics on population growth and hunger are disturbing. Last year the world's population reached 6 billion. And by 2050, the UN estimates, it will be probably near 9 billion. Almost all that growth will occur in developing countries. At the same time, the world's available cultivable land per person is declining. Arable land has declined steadily since 1960 and will decrease by half over the next 50 years, according to the International Service for the Acquisition of Agri-Biotech Applications (ISAAA).
How can biotech help?
Biotechnologists have developed genetically modified rice that is fortified with beta-carotene(β-胡萝卜素)—which the body converts into vitamin A -- and additional iron, mid they are working on other kinds of nutritionally improved crops. Biotech can also improve farming productivity in places where food shortages are caused by crop damage attribution to pests, drought, poor soil and crop viruses, bacteria or fungi (真菌).
Damage caused by pests is incredible. The European corn borer, for example, destroys 40 million tons of the world's corn crops annual]y, about 7% of the total. Incorporating pest-resistant genes into seeds can help restore the balance. In trials of pest-resistant cotton in Africa, yields have increased significantly. So far, fears that genetically modified, pest-resistant crops might kill good insects as well as bad appear unfounded.
Viruses often cause massive failure in staple crops in developing countries. Two years ago, Africa lost more than half its cassava(树薯) crop --- a key source of calories -- to the mosaic virus. Genetically modified, virus-resistant crops can reduce that damage, as can droughttolerant seeds in regions where water shortages limit the amount of land under cultivation. Biotech can also help solve the problem of soil that contains excess aluminum, which can damage roots and cause many staple-crop failures. A gene that helps neutralize aluminum toxicity(毒性) in rice has been identified.
Many scientists believe biotech could raise overall crop productivity in developing countries as much as 25% and help prevent the loss of those crops after they are harvested.
Yet for all that promise, biotech is far from being the whole answer. In developing countries, lost crops are only one cause of hunger. Poverty plays the largest role. Today more than I billion people around the globe live on less than I dollar a day. Making genetically modified crops available will not reduce hunger if farmers cannot afford to grow them or if the local population cannot afford to buy the food those farmers produce.
Biotech has its own "distribution" problems. Private-sector biotech companies in the rich countries carry out much of the leading-edge research on genetically modified crops. Their products are often too costly for poor farmers in the developing world, and many of those products won't even reach the regions where they are most needed. Biotech firms have a strong financial incentive to target rich markets first in order to help them rapidly recoup the high costs of product development. But some of these companies are responding to needs of poor countries.
More and more biotech research is being carried out in developing countries. But to increase the impact of genetic research on tile food production of those countries, there is a need for better collaboration between government agencies -- both local and in developed countries -- and private biotech firms. The ISAAA, for example, is successfully partnering with the US Agency for International Development, local researches and private biotech companies to find and deliver biotech solutions for farmers in developing countries.
Will "Franken-foods" feed the world?
Biotech is not a panacea(治百病的药), but it does promise to transform agriculture in many developing countries. If that promise is not fulfilled, the real losers will be their people, who could suffer for years to come.
The world seems increasingly to have been 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 perfectly 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 world's burgeoning(迅速发展的) population. Skeptics contend that genetically modified crops could pose unique risks to the environment and to health -- risks too troubling to accept placidly. Taking that view, many European countries are restricting the planting and importation of genetically modified agricultural products. Much of the debate hinges on perceptions of safety. But what exactly does recent scientific research say about the hazards?
Two years ago in Edinburgh, Scotland, eco-vandals stormed a field, crushing canola plants. Last year in Maine, midnight raiders hacked down more than 3,000 experimental poplar trees. And in San Diego, protesters smashed 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 genetically modified varieties.
It's easy to understand why. In a way, genetically modified crops -- now on some 109 million acres of farmland worldwide -- are invisible. You can't see, taste or touch a gene inserted into a plant or sense its effects on the environment. You can't tell, just by looking, whether pollen containing a foreign gene can poison butterflies or fertilize plants miles away. That invisibility is precisely what worries people. How, exactly, will genetically modified crops affect the environment -- and when will we notice?
Advocates of genetically modified or transgenic crops say the plants will benefit the environment by requiring fewer toxic pesticides than conventional crops. But critics fear the potential 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. "There's a lot we don't know and need to find out."
As genetically modified crops multiply in the landscape, unprecedented numbers of researchers have started fanning into the fields to get the missing information. Some of their recent findings are reassuring; others suggest a need for vigilance.
1. Majority of people in those countries maintaining a long history of agriculture believe ______.
A) genetically modified crop is beneficial
B) genetically modified crop causes environmental problems
C) high-tech crop is a great benefit to the world
D) genetically modified foods is a heated topic

[定位] 由题干中的majority of people in．．．和long history of agriculture能够定位到第一段第二、三句For many people，the concept of geneti cally altered，high-tech crop production raises all kinds of environmental．．．Particmlary in countries．．．the idea seems against nature．
[精解] 题干中的majority of people和文章中的many people意思相近；题干中的long history of agriculture意为“悠久的农业历史”，与文章第一段最后一句中的long agrarian traditions意思相同；分析定位句能够得出大多数的人，特别是有悠久农业历史的国家的人普遍认为转基因作物会引起环境、健康等问题，因此本题答案为B)。

答案:B
2. How much genetically modified corn was planted in the US last year?
A) More than half. B) 65 million acres. C) One third. D) Three quarters.

[定位] 根据题干中的genetically modified com 和 in the US last year能够迅速定位到文章的第二段第二句 A third of the com．．．grown in the US last year were the product of biotechnology，．．．．
[精解] 根据定位句可知，去年的转基因玉米的种植面积占到三分之一，转基因大豆和棉花种植面积占到一半多。因此本题答案应为C)。

答案:C
3. Why is the debate on genetically modified foods more heated in developing countries?
A) Because they have a rich range of foods. B) Because the supply outstrips the need.
C) Because they have to feed fast-growing populations. D) Because the risks outweigh the benefits.

[定位] 根据题干中的debate on genetically modified foods 和 heated in developing countries能够定位到第三段第四句In developing countries desperate to feed fast-growing and underfed populations．．．

[精解] 第三段讨论的是发达国家和发展中国家对待转基因食品的态度。由于发达国家的食品种类丰富而且供过于求，因此debate about biotech is tempered(缓和的)；而发展中国家人口增长迅速且大多吃不饱，需要大量食品，因此对于是否要采用转基因食品来解决人口和健康问题就显得很迫切。由此可知C)为本题答案。

答案:C
4. According to the UN's prediction, the growth population from now to 2050 is nearly all in ______.
A) western countries B) African countries
C) developed countries D) developing countries

[定位] ，根据题干中的According to the UN's prediction，the growth population from now to 2050能够定位到第四段的第三句And by 2050，the UN estimates，it will probably near 9 billion．Almost all that growth will occur in developing countries．
[精解] 根据题干在文章中的定位，题干中的prediction和文章中的estimate是同义词，都是“估计，预测”的意思；题干中的nearly和文章中的almost也是同义词；而第四句中的that指代的就是第三句中联合国估计的增长人口；occur有“发生，出现”的意思；即增长的人口几乎都发生在developing countries因此，本题答案为D)。

答案:D
5. Genetically modified crops can help to improve ______.
A) nutrient contents and farming productivity B) beta-carotene contents in rice
C) vitamin A and iron elements in crop D) attribution to resist insects

[定位] 根据题干中的Genetically modified crops can help to improve能够定位到第一个小标题下的第一段第二句Biotech can also improve farming productivity．．．
[精解] 分析题干可知，本题考查的是对文章内容的总结能力。该段第一句主要讲述了生物科技改进大米及其它作物的营养成分；第二句讲述了生物科技改进农业生产力。由此可知转基因作物能改进作物的营养成分和农业生产力。故本题答案为A)。

答案:A
6. What was the reason that led to the loss of more than half of African main food two years ago?
A) Drought. B) Toxin in the crop. C) The mosaic virus. D) The barren soil.

[定位] 根据题干中的led to the loss of more than half of African main food two years ago能够定位到第一个小标题下的第三段第二句Two years ago，Africa lost more than half its cassava crop—a key source of calories-to the mosaic virus．
[精解] 题干考查的是两年前导致非洲玉米主要食物损失一半以上的原因。根据定位句，能够找出题干中所指的main food指的是文章中的a key source of calories，即cassava crop；因此，根据定位句可知这一损失是由the mosaic virus引起的。因此本题答案为C)。

答案:C
7. The most important factor that leads to hunger in developing countries is ______.
A) lost crops B) global greenhouse effect
C) economic crisis D) poverty

[定位] 根据题干中的The most important factor that leads to hunger能够定位到第一个小标题下的第五段第二、三句In developing countries，lost crops are only one cause of hunger．Poverty plays the largest role，
[精解] 定位句讲到了lost crops是导致饥饿的一个因素，接着在第三句中讲到poverty扮演着最大的角色，其中在the largest role后省略了in causing hunger。因此，本题答案为D)。

答案:D
8. Those people and countries which are restricting and opposed to genetically modified plants worry about ______.

[定位] 由题干中的．，．are restricting and opposed to genetically modified plants，．．能够定位到第二个小标题下的第二段倒数第三句Taking that view，many European countries are restricting the planting and importation of genetically modified agricultural products．
[精解] 定位句中讲到“许多欧洲国家严格限制转基因农作物产品的种植和进口”，而在下一句指出“主要的争议集中在基因改造食物的安全性”(Much of the debate hinges on perceptions of safety．)，因此在题干的空白处应填入the safety of genetically modified food。
答案:the safety of genetically modified food
9. The far-flung outrage destroys fields and plants because they misidentified _______.

[定位] 根据题干中的The far-flung outrage destroys fields and plants定位到第二个小标题下的第四段This farflung 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 genetically modified varieties．
[精解] 题干中的misidentified和文章中的mistook都有“弄错，误解”的意思，因此mistook后面所跟的短语ordinary plants for genetically modified varieties即是本题的答案。

答案:ordinary plants for genetically modified varieties
10. Some people boost genetically modified crops on the condition that these altered plants contain ______.
[定位] 根据题干中的Some people boost genetically modified crops．．．能够定位到第二个小标题下的第六段第一句Advocates of genetically modified or transgenic crops say the plants will benefit the environment by requiring fewer toxic pesticides than conventional crops．
[精解] 题干中的people boost genetically modified crops和文章中的advocates of genetically modified or transgenic crops属于同义转换；而原文是will．．．by．．．结构表示“在一定的条件下将会……”，与题干中的on the condition that属于同义结构转换；原文中的require与题干中的contain意思相近，故requiring后面的内容 fewer toxic pesticides即是本题的答案。

答案:fewer toxic pesticides

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