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问题 单项选择题

增加离心泵出口的管路阻力，则泵出口压力和流量的变化为（）。

A、压力增加，流量增加

B、压力增加，流量减少

C、压力下降，流量增加

D、压力下降，流量下降

答案

参考答案：B

填空题

根据短文内容，从短文后的选项中选出适当的选项补全短文，将选项的编号依次填人题后的横线上。

Do you laugh every day? Most people do．  1 That is a lot of laughter．

In India，there are hundreds of laughter clubs．  2 First they put up their hands above their heads．Then they pretend to laugh．Soon everyone is laughing happily．People say they feel good after laughing together．

Scientists believe that laughter is good for you．Why? For one thing，laughter is good exercise．  3 Scientists say that one hundred laughs equals ten minutes of running．Laughing helps you relax．That’s good for you，too．

Why do we laugh? That is a hard question to answer．  4 They don’t laugh very often when they are alone．Many scientists believe that we use laughter to get on well with other people．Laughter helps us feel part of a group．

5 Some think that laughter makes sick people get better．Do you think so，too?
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单项选择题

某市政工程划分为3个施工过程在5个施工段组织加快的成倍节拍流水施工，流水节拍值分别为4、4、2天，该工程的流水施212212期为（）天。

A．26

B．24

C．18

D．16
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