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问题 单项选择题

声波在水／钢介面的声压反射率和声压透过率为（）。

（Z水=1.5×10公斤平方米•秒，Z钢=4.5×10公斤／平方米•秒）

A、60%、200%

B、40%、100%

C、50%、150%

D、20%、100%

答案

参考答案：C

填空题

在0、1、7、8中选出3个数字，组成一个能同时被3、5整除的最小三位数是______．
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单项选择题

Airplane manufacturer: I object to your characterization of our X-387 jets as dangerous. No X-387 in commercial use has ever crashed or even had a serious malfunction.
Airline regulator: The problem with the X-387 is not that it, itself, malfunctions, but that it creates a turbulence in its wake that can create hazardous conditions for aircraft in its vicinity.
The airline regulator responds to the manufacturer by doing which of the following

A．Characterizing the manufacturer’s assertion as stemming from subjective interest rather than from objective evaluation of the facts.

B．Drawing attention to the fact that the manufacturer’s interpretation of the word "dangerous" is too narrow.

C．Invoking evidence that the manufacturer has explicitly dismissed as irrelevant to the point at issue.

D．Citing statistical evidence that refutes the manufacturer’s claim.

E．(E) Casting doubt on the extent of the manufacturer’s knowledge of the number of recent airline disasters.
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