Do you think there is too much noise in our city? If you live near an airport,you will be unhappy because of a plane often make a loud noise.The sound of planes or heavy vehicles is likely to cause deafness if heard continuously . However, most people in our city do not seem to mind noise. They like to enjoy music when they are doing uninteresting jobs.It is a new danger because pop music,when played through powerful amplifiers ,can reach 120 decibels(120)at a distance of five feet.A continuous noise of over 85 decibels can cause deafness.It was discovered that many young people in America could hear no better than 65-year-old people. In the past we used to think that only workers in very noisy places would become deaf.For example,when newspapers and books are being printed,the noise level is over 85 decibels,and some of the workers become deaf.Today,however,scientists believe that 10 percent of the workers in Britain are being deafened by the noise. Sometimes noise of less than 85 decibels can make some people tired and stressed.We all know that too much noise makes life difficult and unpleasant.It can do great harm to people's health and prevent people from working well.Workers in noisy offices are not as efficient as those in quiet offices.Noise makes people less efficient.Can anything be done to reduce or control noise? In Britain the government has made several laws to reduce noise.Though the government has spent a lot of money in making airports and main roads quieter,many people think that there are still not enough laws.For example,there are no laws to control the noise of machines.In Japan,America and Norway there are such laws.As a result,workers can be given compensation if they become deaf. In Britain there are laws to   _  .
stop workers from becoming deaf control the noise of machines keep down noise help deaf workers in need