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问题 单项选择题

有一个深50 m，顶圆半径为100 m的圆锥形储水器储满了水，假设水位以0.02 m/h的速度均匀下降，当水深为30 m时，水池水量的流失速度是（）。

A.32πm/h

B.42πm/h

C.52πm/h

D.62πm/h

E.72πm/h

答案

参考答案：E

完形填空

课文填空（共9小题；每小题1分，满分9分）

_____小题1:______ a calculating machine, I could__小题2:______ difficult sums. I developed slowly for hundreds of years until I was made to work as a “universal machine”. From then on, I grew ____小题3:______  both in___小题4:______ and in brainpower .Then as my memory improved, I changed my ____小题5:_______ to a much smaller one. But I have to stand there by myself, feeling so ______小题6:_____ . Since the 1970s, many new applications _____小题7:______ (find) for me and I have become very important in communication, finance and trade. To provide humans with a life of high___小题8:_____ is what I am all about. I am really proud that I am a_____小题9:_____  friend and helper of the human race.
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单项选择题

深圳地铁首班车到站前（）分钟，值班站长打开车站正常照明。

A、5

B、10

C、15

D、20
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