Life gets noisier every day and very few people can free from noise of some sort or another. It doesn’ t matter where you live—in the middle of a modem city, or a faraway village—the chances that you will be disturbed by jet aeroplanes, transistor radios, oil powered engines, etc. , are almost everywhere. We seem to be getting used to noise, too. Some people feel quite lonely without back-ground music while they are working. Scientific tests have shown that total silence can be very frightening experience for human beings. However,some people enjoy listening to pop music which is very loud,and this can do harm to their eardrums (耳鼓).The noise level in some disco is far above the usual safety level for heavy industrial areas. One recent report about noise and concentration (专心)suggested that although a lot of people say that any noise disturbs their concentration, what really affects their ability to concentrate is a change in the level of noise. It goes on to say that a background noise, which doesn’ t change too much (music,for example) may even help people to concentrate. From this passage,the pollution of noise____. A.doesn’ t matter much B.has become worse everywhere C.has become better in big cities D.has become better in villages “Background music” in the passage means____.A.music played in the concert B.a kind of noise coming into your ears C.music which helps people to concentrate D.music played while people are working Some people may have their hearing hurt____.A.while they are in complete silence B.while they are dancing violently C.while they are listening to pop music D.while they are listening to soft music Scientists have discovered that what prevents people from concentrating is____.A.any kind of noise B.great changes in level of noise C.background noise D.various background music