问题详情：
In today’s world, almost everyone knows that air pollution and water pollution are harmful to people’ health. However, not all the persons know that noise is also a kind of pollution, and this is harmful to people’ health, too.
People who work and live under noisy conditions usually become deaf today. However, scientists believe that 10 percent of workers in Britain are being deafened by the noise where they work. Many of the workers who print newspapers and books, and who weave（编织） cloth become deaf. Quite a few people living near airports also become deaf. Recently it was discovered that many teenagers in America could hear no better than 65-year-old persons, for these young people like to listen to pop music and pop music is a kind of noise, Besides, noise produced by jet planes or machines will make people ill or even drive them mad.
It is said a continuous noise of over 85 decibels（分贝）can cause deafness. Now the government in many countries have made laws to control noise and make it less than 85 decibels.
In China, the government is trying to solve not only air and water pollution problems but also noise problems.
28. The text is mainly about ______.
A. air pollution B. water pollution C. noise pollution D. world pollution
29. According to the text, a continuous noise of _____decibels can make people deaf.
A. less than 85 B. less than 65 C. about 65 D. more than 85
30. Ten percent of the workers in Britain are being deafened because ______.
A. they are working in noisy places B. they often listen to pop music
C. they are busy in listening to other’s talk D. they live near airports
31. The government of China is trying to solve ______.
A. only air pollution B. only air and water pollution
C. only water pollution D. air, water and noise pollution
【回答】
CDAD
知识点：阅读理解
题型：阅读理解
