4.Jingle Bells 《铃儿响叮当》，西方国家十分流行的一首圣诞节歌曲。
1.The shop workers in the Western world are glad when Christmas is over because they don’t have to
A)rush their feet off all day.
B)listen to the music playing au the time in the shop.
C)work overtime to make more profits for the boss.
D)try to please the customers.
2.It has been proved that listening to simple，happy has a good effect on
A)cows.
B)workers.
C)customers.
D)bosses.
3.Which of the following statements is true，according to the research findings reported in paragraph 6？
A)Repeated hearings of complex pieces of music are enjoyable and not tiresome.
B)Repeated hearings of complex pieces of music are tiresome at first and then become enjoyable.
C)Repeated hearings of simple songs are more enjoyable than those of complex pieces of music.
D)Repeated hearings of simple songs become tiresome sooner than those of complex pieces of music.
4.In hostage situations the US police forces repeatedly play pop songs at high volume in order to
A)put pressure on the criminals.
B)distract the attention of the criminals.
C)keep the criminals awake.
D)please the criminals.
5.According to the article，which of the following most appropriately indicates the nature of the effect repeated hearing of the same tune produces on the hearer？
A)Social.
B)Physical.
C)Psychological.
D)Both physical and psychological.