题目内容
When did ozone problems first become known？
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Part A
Directions: Read the following four texts. Answer the questions below each text by choosing A, B, C or D . Mark your answers on ANSWER SHEET 1.
Many Americans have a grossly distorted and exaggerated view of most of the risks surrounding food. Fergus Clydesdale, head of the department of food science and nutrition at the University of Massachusetts-Amherst, says bluntly that if the dangers from bacterially contaminated chicken were as great as some people believe, "The streets would be littered with people lying here and there."
Though the public increasingly demands no-risk food, there is no such thing. Bruce Ames, chairman of the biochemistry department at the University of California, Berkeley, points out that up to 10% of a plant's weight is made up of natural pesticides, says he: "Since plants do not have jaws or teeth to protect themselves, they employ chemical warfare." And many naturally produced chemicals, though occurring in tiny amounts, prove in laboratory tests to be strong carcinogens—a substance which can cause cancer. Mushrooms might be banned if they were judged by the same standard that apply to food additives. Declares Christina Stark, a nutritionist at Cornell University: "We've got far worse natural chemicals in the food supply than anything man-made."
Yet the issues are not that simple. While Americans have no reason to be terrified to sit down at the dinner table, they have every reason to demand significant improvements in food and water safety. They unconsciously and unwillingly take in too much of too many dangerous chemicals. If food already contains natural carcinogens, it does not make much sense to add dozens of new man-made ones. Though most people will withstand the small amounts of contaminants generally found in food and water, at least a few individuals will probably get cancer one day because of what they eat and drink.
To make good food and water supplies even better, the Government needs to tighten its regulatory standards, stiffen its inspection program and strengthen its enforcement policies. The food industry should modify some long-accepted practices or turn to less hazardous alternatives. Perhaps most important, consumers will have to do a better job of learning how to handle and cook food properly, The problems that need to be tackled exist all along the food-supply chain, from fields to processing plants to kitchens.
What does the author think of the Americans' view of their food？
The Nile is a highway for the people of Egypt. Flat bottomed boats and large narrow barges carry products from one city to another. There are also passenger boats on the Nile, carrying people up and down the river. In ancient times huge blocks of stones were floated down the river on barges. These stones are used in making buildings and monuments.
For thousands of years the Egyptians have depended on the Nile for their crops. The land on both sides of the Nile is desert, where crops cannot be raised. But crops grow well in the Nile Valley. In fact, several different crops are often grown on the same land during the same year.
Once the Nile flooded each year, overflowed its banks, and carried rich soil in land every summer. These floods were caused by early summer rains.
At present there is a series of dams on the Nile. Water raised high in the river each summer as usual. The people do not let the Nile flood, however. They store the water behind dams. It is now possible to use the water as needed, not just at flood time.
In the past______.
Egyptians have grown crops well______.
Why does Ms. Rowling consider herself very luck？
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