14年12月大学英语六级阅读模拟题:长篇阅读

2014-12-08 15:49:43 字体放大:  

How can biotech help?

[E] Biotechnologists have developed genetically modified rice that is fortified with beta-carotene(胡萝卜素)--which the body converts into vitamin A--and additional iron, and 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 ).

[F] Damage caused by pests is incredible. The European corn borer, for example, destroys 40 million tons of the-world's corn crops annually, 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.

[G] 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 (花叶病毒).Genetically modified, virus-resistant crops can reduce that damage, as can drought-tolerant 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.

[H]Yet for all that promise, biotech is far from being the whole answer. In developing countries, lost crops are only one cause ofhunger. Poverty plays the largest role. Today more than 1 billion people around the globe live on less than 1 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.

[I] 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.

[J] More and more biotech research is being carried out in developing countries. But to increase the impact of genetic research on the 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 U. S. 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?

[K]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.

[L] The world seems increasingly to have been divided into those who favor genetically modified 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 cultivation and importation of genetically modified agricultural products. Much of the debate are concerned about of safety. But what exactly does recent scientific research say about the hazards?

[M] 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.

[N] 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?

[O] 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 soft 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.

46. According to the UN's prediction, the population growth from now to 2050 is nearly all in developing countries.

47. Those people and countries restricting and opposed to planting and importing of genetically modified $ plants worry about their safety.

48. The boosters of genetically modified crops argue that these altered plants need fewer toxic pesticides.

49. The mosaic virus led to the loss of more than half of African main food two years ago.

50. Genetically modified crops can help to improve nutrient contents and farming productivity.

51. The most important factor that leads to hunger in developing countries is poverty, not crops lost.

52. The far-flung outrage destroys fields and plants because they misidentified ordinary plants for genetically modified varieties.

53. The debate on genetically modified foods is more heated in developing countries with fast-growing and half-starved populations.

54. One third of corn planted in America was genetically modified corn last year.

55. Majority of people believe genetically modified crop causes environmental problems.