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单选题 Genetically Modified Foods If you want to spark a heated debate at a dinner party, bring up the topic of genetically modified foods. For many people, the concept of genetically altered, high-tech crop production raises all kinds of environmental, healthy, safety and ethical questions. Particularly in countries with long a grain traditions-and vocal green lobbies—the idea seems against nature. In fact, genetically modified foods are already very much apart of out lives. A third of the cornand more than half the soybeans and cotton grown in the U.S. 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 U.S. this year. The genetic genie (妖怪) is out of the bottle. Yet there are clearly some very real issues that need to be resolved. Like any new product entering the food chain, genetically modified foods must be subjected to rigorous testing. In wealthy countries, 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. The U.N. estimates that nearly 800 million people around the world are undernourished. The effects are devastating. About 400 million women of child-bearing age are iron deficient, which means their babies are exposed to various birth defects. As many as 100 million children suffer from vitamin A deficiency, a leading cause of blindness. How can biotech help? Biotechnologists have developed genetically modified rice that is fortified with beta-carotene-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 attributable to pests, drought, poor soil and crop viruses, bacteria or fungi.
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单选题Mary is {{U}}looking for{{/U}} the book she lost yesterday A. trying to find B. trying to read C. trying to buy D. trying to borrow
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单选题Many of Europe"s airports are heavily congested .
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单选题The trumpet was part of the opera orchestra long before it became a standard orchestral instrument.
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单选题Tonight"s live coverage of the hockey (曲棍球) game is very wonderful.
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单选题How do you interpret the sentence 'her airplane Electra is not pressurized' (Para. 4)?
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单选题They had a far better {{U}}yield{{/U}} than any other farm miles around this year.
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单选题Our arrangements were thrown into complete turmoil .
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单选题The leaves have been swept into huge {{U}}heaps {{/U}}.
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单选题The governor gave a rather vague outline of his tax plan.
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单选题The phobia may have its root in a childhood trauma .
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单选题The leaves have been swept into huge {{U}}heaps{{/U}}. A.loads B.layers C.pyramids D.piles
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单选题We lived for years in a {{U}}perpetual{{/U}} state of fear
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单选题Changes in Museums Museums have changed. They are no longer places that one "should" visit, they are places to enjoy and learn. At a science museum in Ontario, Canada, you can feel your hair stand on end as harmless electricity passes through your body. At the Metropolitan (成都市的) Museum of Art in New York City, you can look at the seventeenth century instruments while listening to their music. At New York's American Museum of Natural History recently, you can help make a bone-by-bone reproduction of the museum's dinosaur(恐龙), a beast that lived 200 million years age. More and more museum directors are realizing that people learn best when they can somehow become part of what they are seeing. In many science museums, for example, there are no guided tours. The visitor is encouraged to touch, listen, operate, and experiment so as to discover scientific principles for himself. The purpose is not only to provide fun but also to help people feel at home in the world of science. The theory is that people who do not understand science will probably fear it, and those who fear science will not use it to best advantage. One cause of all these changes is the increase in wealth and leisure time. Another cause is the rising percentage of young people in the population. Many of these young people are college students or college graduates, Leon F. Twiggs, a young black professor of art once said, "They see things in a new and different way. They are not satisfied to stand and look at works of art; they want art they can participate(参加) in. "The same is true of science and history.
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单选题It seems highly unlikely that she will pass the exam.
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单选题The industrial revolution modified the whole structure of English society.
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单选题下面有3篇短文,每篇短文后有5道题,每题后面有4个选项。请仔细阅读短文并根据短文回答其后面的问题,从4个选项中选择1个最佳答。{{B}}第一篇{{/B}} {{B}}Food and Health{{/B}} The food you eat does more than provide energy. It can have a dramatic effect on your body’s ability to fight off heart disease, cancer, diabetes, high blood pressure, stroke, and weak bones. With remarkable consistency, recent research has found that a diet high in plant-based foods—fruits, vegetables, dried peas and beans, grains, and starchy staples such as potatoes—is the body’s best weapon in {{U}}thwarting{{/U}} many health-related problems. These foods work against so many diseases that the same healthy ingredients you might use to protect your heart or ward off cancer will also benefit your intestinal tract and bones. Scientists have recently estimated that approximately 30 to 40 percent of all cancers could be avoided if people ate more fruits, vegetables, and plant-based foods and minimized high-fat, high-calorie edibles that have scant nutritional value. Up to 70 percent of cancers might be eliminated if people also stopped smoking, exercised regularly, and controlled their weight. In the past, researchers had linked fat consumption with the development of cancers, but they currently believe that eating fruits, vegetables, and grains may be more important in preventing the disease than not eating fat. “The evidence about a high-fat diet and cancer seemed a lot stronger several years ago than it does now,” says Melanie Polk, a registered dietitian and director of nutrition education at the American Institute for Cancer Research. The road to strong bones is paved with calcium-rich food. Leafy green vegetables and low-fat dairy products are excellent sources of calcium, the mineral that puts stiffness into your skeletal system and keeps your bones from turning rubbery and fragile. Your body uses calcium for more than keeping your bones strong. Calcium permits cells to divide, regulates muscle contraction and relaxation, and plays an important role in the movement of protein and nutrients inside cells. If you don’t absorb enough from what you eat to satisfy these requirements, your body will take it from your bones. Because your body doesn’t produce this essential mineral, you must continually replenish the supply. Even though the recommended daily amount is 1,200 mg, most adults don’t eat more than 500 mg. One reason may have been the perception that calcium-rich dairy products were also loaded with calories. “In the past, women, in particular, worried that dairy products were high in calories,” says Letha Y. Griffin, M. D., of Peachtree Orthopaedics in Atlanta. “But today you can get calcium without eating any high-fat or high-calorie foods by choosing skim milk or low-fat yogurt.” Also, low fat dairy products contain phosphorous and magnesium and are generally fortified with vitamin D, all of which help your body absorb and use calcium. If you find it difficult to include enough calcium in your diet, ask your doctor about supplements. They’re a potent way to get calcium as well as vitamin D and other minerals. But if you rely on pills instead of a calcium-rich diet, you won’t benefit from the other nutrients that food provides. Getting the recommended vitamin D may be easy, since your body makes the vitamin when your skin is exposed to the sun’s rays.
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单选题People's attitudes to the TV program have changed a lot.A. displayedB. shownC. shiftedD. described
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单选题I have extreme sense of happiness at this moment.A. hopeB. wishC. feelingD. dream
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单选题She has proved that she can be {{U}}relied on{{/U}} in a crisis.
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