2016年6月大学英语四级考试模拟卷及答案解析(二)

　　Americans may face even more urgent problems from pollution. Drinking water in the United States is generally safe and meets high standards. Nevertheless, one in five Americans every day unknowingly drinks tap water contaminated with bacteria and chemical wastes, according to the Environmental Protection Agency. In Milwaukee, 400,000 people fell ill in 1993 after drinking tap water tainted with cryptosporidium, a microbe that causes fever, diarrhea and vomiting.

　　The Source

　　Where so contaminants come from? In developing countries, people dump raw sewage into the same streams and rivers from which they draw water for drinking and cooking; about 250 million people a year get sick from water borne diseases.

　　In developed countries, manufacturers use 100,000 chemical compounds to make a wide range of products. Toxic chemicals pollute water when released untreated into rivers and lakes. (Certain compounds, such as polychlorinated biphenyls, or PCBs, have been banned in the United States.)

　　But almost everyone contributes to water pollution. People often pour household cleaners, car antifreeze, and paint thinners down the drain; All of these contain hazardous chemicals. Scientists studying water in the San Francisco Bay reported in 1996 that 70 percent of the pollutants could be traced to household waste.

　　Farmers have been criticized for overusing herbicides and pesticides, chemicals that kill weeds and insects but insects but that pollutes water as well. Farmers also use nitrates, nitrogenrich fertilizer that helps plants grow but that can wreak havoc on the environment. Nitrates are swept away by surface runoff to lakes and seas. Too many nitrates "over enrich" these bodies of water, encouraging the buildup of algae, or microscopic plants that live on the surface of the water. Algae deprive the water of oxygen that fish need to survive, at times choking off life in an entire body of water.

　　What's the Solution?

　　Water expert Gleick advocates conservation and local solutions to waterrelated problems; governments, for instance, would be better off building smallscale dams rather than huge and disruptive projects like the one that ruined the Aral Sea.

　　"More than 1 billion people worldwide don't have access to basic clean drinking water," says Gleick. "There has to be a strong push on the part of everyonegovernments and ordinary people-to make sure we have a resource so fundamental to life."

　　1. That the huge water projects have diverted the rivers causes the Aral Sea to shrink.

　　2. The construction of massive dams and irrigation projects does more good than harm.

　　3. The chief causes of water shortage are population growth and water pollution.

　　4. The problems Americans face concerning water are ground water shrinkage and tap water pollution.

　　5. According to the passage all water pollutants come from household waste.

　　6. The people living in the United States will not be faced with water shortages.

　　7. Water expert Gleick has come up with the best solution to water related problems.

　　1.[Y][N][NG]2.[Y][N][NG]3.[Y][N][NG]4.[Y][N][NG]

　　5.[Y][N][NG]6.[Y][N][NG]7.[Y][N][NG]

　　8. According to Peter H. Gleick, by the year 2025, as many as of the world's people will suffer from water shortages.

　　9.Two thirds of the freshwater on Earth is locked in.

　　10.In developed countries, before toxic chemicals are released into rivers and lakes, they should be treated in order to avoid.