Part Ⅱ Reading Comprehension (Skimming and Scanning)Directions: In this part, you will hav
Part Ⅱ Reading Comprehension (Skimming and Scanning)
Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1. For questions 1-7, choose the best answer from the four choices marked A), B), C) and D). For questions 8-10, complete the sentences with the information given in the passage.
Genetically Modified Foods -- Feed the World?
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 fast-growing 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 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
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