问题 问答题 简答题

压力管道的水击(水锤)现象有何危害?

答案

参考答案:

水击现象发生时,压力升高值可能为正常压力的好多倍,使管壁材料承受很大的压力;压力的反复变化,会引起管道和设备的振动,严重时会造成管道、管道附件及设备的损坏。

填空题

请阅读下列短文。根据短文内容从下面方框的七个选项中,选择五个适当的句子还原到原文中,使短文意思通顺、结构完整,并将其答案填写到答题卷的相应位置。(每小题2分)

The history of the fortune cookie

Do you know about fortune cookie?

小题1:         They not only taste good, but also have a surprise inside. It is a small piece of paper with a meaningful saying printed on it. These sayings usually give people some food for thought.

小题2:         Because Chinese restaurants in China Town usually give customers some free fortune cookies. However, they originated in (起源于) America 小题3:             But some people believe that a Chinese immigrant (移民) , David Jung, invented the fortune cookie in 1918.

David Jung lived in Los Angeles and was the founder of the Hong Kong Noodle Company. He cared about all the poor he saw in the streets hear his shop. 小题4:       Each cookie had an inspirational verse (鼓舞人心的诗句)inside it.

小题5:         But it is the "fortune" inside that matters.

A.No one is sure about who invented the cookie.

B.The fortune cookies have a long history.

C.So he created the cookies and gave they away for free.

D.If you eat the cookies, you'll be a lucky person soon.E. Many people think fortune cookies came from China.

F. That who actually invented the fortune cookie is not important

G. They are common in foreign countries' Chinese restaurants.

单项选择题