下述关于管道的水头损失，说法不正确的是( )。 A．管道倒流

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问题单项选择题

下述关于管道的水头损失，说法不正确的是( )。

A．管道倒流防止器的局部水头损失，宜取0.025～0.04MPa
B．管道过滤器的局部水头损失，宜取0.01MPa
C．比例或减压阀的水头损失，阀后动水压宜按阀后静水压的80%～90%采用
D．管道过滤器的局部水头损失，宜取0.02MPa

答案

参考答案：D

阅读理解

阅读短文并判断正(√)误 (×) 。

I like winter. It is fun. There is ice and snow. We can skate and ski. We can make snowmen, too. I put on

my hat, scarf, mitts and winter jacket because it is cold outside. I don't like summer, because it is too hot. I like

spring because I like the rain. But I don't like to get wet. I always have my boots and umbrella on a rainy day.

( ) 1. I like winter and spring, but I don't like fall.

( ) 2. There is ice and snow in winter and it is cold.

( ) 3. I don't like summer, because I can't make a snowman.

( ) 4. I like the rain, but I don't like to get wet.

选择题

下列对三国鼎立局面的评价，哪一项是符合历史发展趋势的？ [ ]

A．战乱频繁，破坏了社会经济

B．三国鼎立，加剧了国家的分裂

C．破坏了民族关系，不利于民族融合

D．局部统一，为全国统一创造了条件