最新预测：07年6月六级新题型试卷及答案（五）

  

Acid rain is a very serious air and water pollution problem. Many people feel that it is the most serious pollution problem that we now face. Scientists say that plant and animal life in thousands of lakes in the United States and Canada has already been destroyed by acid rain.

Acid rain forms in the upper atmosphere. There, sulfur dioxide and nitrogen oxides mix with water vapor. They mix with water vapor to form sulfuric acid and nitric acid. When the vapor condenses and rain falls, the acids fall with it. Every time acid rain falls in a lake, the level of acid in the lake rises. Over time, it can rise to the point at which plants and insects cannot survive. Without plants, which supply oxygen, and insects, which supply food, fish die. The lake becomes a dead lake.

The problem of acid rain has greatly increased in the last few years. Most of the blame for acid rain has been placed on industries. However, some people feel that ineffective air pollution laws are also to blame for the acid rain problem.

A few years ago, many cities and states passed local air pollution laws. The laws were written to improve the air quality in the cities and states. However, the laws usually didn't say anything about the amount of pollution that an industry could pump into the air. Industries found a way to meet the new pollution laws without reducing the amount of pollution they released. They met the new standards by building taller smokestacks.

With the taller smokestacks, air pollutants were released higher up into the atmosphere. The wind carried them far away from the polluting factory. To the people near the factory, the air seemed cleaner. However, the pollution that they once got was now coming down hundreds of miles away in the form of acid rain.

26. Which of the following is TRUE about acid rain?

A. It is acknowledged by scientists to be the most serious pollution problem that human beings now face.

B. Many endangered species are on the verge of extinction because of acid rain.

C. Acid rain is composed of sulfur dioxide and nitrogen oxides mixed with water vapor found in the upper atmosphere.

D. Acid rain is mostly found in the United States and Canada.

27. Why do lakes in the United States and Canada become dead lakes?

A. Fish in the lakes die because acid rain deprives them of oxygen.

B. Fish in the lakes die from taking in poisonous substances released from the acids.

C. Fish in the lakes die from direct contact with accumulated acid in the water.

D. Air pollutants are dissolved in the water and thus kill the fish.

28. Why didn't the state and local air pollution laws achieve the end of reducing pollution?

A. Industries tend to disregard the laws because they don't want to spend extra money on the processing of industrial wastes.

B. Although measures are taken to send industrial pollutants higher up the atmosphere the amount of industrial pollutants remains the same.

C. The smokestacks built to release pollutants are not tall enough.

D. Only a small number of industries are equipped to live up to the new standards of the air pollution laws.

29. Which of the following can be inferred from the passage?

A. Air pollution laws in the United States and in Canada typically don't specify the amount of pollutants released by industries.

B. The neighboring areas of a factory receive less pollution than distant areas.

C. The number of occurrences of acid rain over the last few years has been on the rise.

D. It is generally believed that ineffective air pollution laws rather than industries are to blame for acid rain.

30. Which is the best title for the passage?

A. Acid Rain: A Environmental Disaster

B. Who Is To Blame?

C. Formation of Acid Rain

D. New State and Local Air Pollution Laws