Stop! Listen! What do you hear? You may hear many different sounds. Some of those sounds may be noisy. Noise is loud and unwanted sound. Noise can be caused by many kinds of machines, such as motorcycles, jet planes, tractors and so on. And, to some people, rock bands are also noise. What happened to people who live near noisy machines or use them over a period of time? Doctors find that these people have trouble in sleeping, But, most important, constant loud noise can cause a loss of hearing. Scientists use a unit of measure called a decibel to measure the loudness of a sound. The sound of a quiet room, for example, measures 35 decibels. Talking measures between 40 and 65 decibels. Sounds from traffic and from some rock bands can measure over 120 decibels. Noise at this high level causes the greatest hearing loss. 小题1: From the article we know noise is ___________. wanted sound               B. loud and unwanted sound C.  all sounds that you can hear    D. comfortable sound 小题2:  A “decibel” is a _________ A．unit that measures sound B．kind of noise C．machine that makes very loud noise D．person who hates noise 小题3:According to the passage, loud noise can ________. help people sleep better         B. stop machine C.  cause a loss of hearing         D. kill people 小题4:The main idea of this passage is that __________ noise pollution can be a serious problem rock bands are noisy noise can cause people to be mad some people hate noise deeply 小题5: Study the chart below, Which room would be the quietest? Room Noise Level A 35 decibels B 120 decibels C 130 decibels D 40 decibels A.  Room A                   B.  Room B C.  Room C                   D.  Room D