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问题 单项选择题

活塞式压缩机有异常的响声和撞击声，但出气温度不高，压力不低，则（）因素可以排除。

A、润滑不恰当

B、气阀安装不正确

C、汽缸余隙太小

D、主轴颈、连杆、十字头销磨损、椭圆度大

答案

参考答案：B

问答题

古时酒席上也划拳吗？
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单项选择题

Noting that the number of crimes committed in a certain city had decreased in 1982 by 5.2 percent in comparison with 1981, the police chief of the city said, "We see here the result of the innovative police program put into effect in the city at the beginning of 1982."
Which of the following, if true, most seriously weakens the conclusion drawn by the police chief

A．Several cities that have recently increased spending for police programs experienced no decrease in crime in 1982, as compared with 198l.

B．The number of crimes committed in the city is estimated, by the same method each year, from the number of crimes reported.

C．The number of crimes committed in the suburban areas surrounding the city rose by about 5 percent in 1982 over the figure for 1981 and were nearly equal in number to those in the city in 1982.

D．The number of crimes committed in the city in 1982 was 10 percent higher than the number committed in 1972.

E．(E) The size of the age group most likely to commit crimes decreased considerably in the city in 1982, as against 1981, because of a declining birth rate.
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