Psychologists now believe that noise has a considerable effect on People's attitudes and behavior. Experiments have proved that in noisy situations (even temporary ones), people be have more irritably and less cooperatively; in more permanent noisy situations, many people cannot work hard, and they suffer from severe anxiety as well as other psychological problems. However, psychologists distinguish between "sound" and "noise". "Sound" is measured physically in decibels. "Noise" cannot be measured in the same way because it refers to the psychological effect of sound and its level of "intensity" depends on the situation. Thus, for passengers at an airport who expect to hear airplanes taking off and landing, there may be a lot of sound, but not much noise (that is, they are not bothered by the noise). By contrast, if you are at a concert and two people behind you are whispering, you feel they are talking noisily even if there is not much sound. You notice the noise because it affects you psychologically. Both sound and noise can have negative effects, but what is most important is if the person has control over the sound. People walking down the street with earphones, listening to music that they enjoy, are receiving a lot of decibels of sound, but they are probably happy hearing sounds which they control. On the other hand, people in the street without earphones must tolerate a lot of noise which they have no control over. It is noise pollution that we need to control in order to help people live more happily.
　　
　11. According to the passage,people _____.
　　 [A] can not work better in a noisy situation
　　 [B] will suffer from complete deafness because of noise pollution
　　 [C] can be psychologically affected by working in very noise factories
　　 [D] may cooperate well in a noisy surrounding

　12. "Sound",as defined by the psychologist,_____.
　　 [A] can be measured in the same way that "noise" is measured
　　 [B] may be extremely harmful to health
　　 [C] is not at all different from "noise"
　　 [D] can be measured by machines

　13. People waiting at an airport _____.
　　 [A] enjoy hearing airplanes taking off and landing
　　 [B] are usually not troubled by the noise
　　 [C] can easily tell sound from noise
　　 [D] are often physically affected by the noise

　14. People enjoy listening to music,_____.
　　 [A] though they are receiving a lot of decibels of sound in fact
　　 [B] because it does not have any negative effect
　　 [C] because they do not have to tolerate the noise around them
　　 [D] even though it is sometimes unpleasant hearing strange sounds

　15. We can conclude from the passage that we need to control noise pollution if _____.
　　 [A] we want to stay both psychologically and physically healthy
　　 [B] we don't want to be physically dent
　　 [C] we want to cooperate well
　　 [D] we don't want to be anxious