问题 问答题 简答题

什么是热工保护?

答案

参考答案:

热工保护是通过对机组工作状态和运行参数进行监视和控制而起保护作用的.当机组发生异常时,保护装置及时发出报警信号,必要时自动启动或切除某些设备或系统,使机组仍然维持原负荷运行或者减负荷运行。当发生重大故障而危及机组设备安全时,停止机组(或某一部分)运行避免事故进一步扩大。热工保护有时是通过联锁控制实现的。

阅读理解

阅读(共两节,15小题;每小题2分,满分30分)

第一节:阅读理解。阅读下列短文,从每题所给的四个选项中,选出最佳选项。

A

This is a true story from Guyana. One day, a boy took a piece of paper from a box. He made a paper ball and pushed it into his nose. He couldn’t get it out. He ran crying to his mother. His mother couldn’t get the paper out, either. A week later, the paper was still in the boy’s nose. His nose began to have a bad smell.

So his mother took the boy to a hospital. The doctor looked up at the child’s nose, but she couldn’t get the paper out. She said she had to cut the boy’s nose to get the paper out.

The boy’s mother came home looking sad. She didn’t want her child to have his nose cut. The next day she took the boy to her friend Sidney who lived in a house with an old lady called May. May wanted to see the child, so the child let her look up his nose.

“Yes, I can see it,” May said. “It will be out soon.”

As she spoke, she shook some black pepper on the child’s nose. The child gave a mighty sneeze and the paper flew out. His mother was surprised. May told his mother to take the boy to the seaside for a swim, for the salt water would go up his nose and stop the bad smell.

So the lucky boy didn’t have to go to the hospital to have his nose cut.

41. After the boy pushed a paper ball into his nose, ____.

A. he took it out                B. his mother took it out

C. he did nothing but cry         D. he tried to take it out but failed

42. The paper ball stayed in the boy’s nose for ____.

A. at most seven days             B. less than seven days

C. more than seven days           D. exactly seven days

43. According to the story, _____ was most worried about the boy’s accident.

A. the boy’s mother     B. Sidney       C. May       D. the doctor

44. Which of the following is TRUE?

A. The doctor helped to take the paper ball out of the boy’s nose.

B. May succeeded in taking the paper out.

C. The boy’s mother found some black pepper to solve the problem.

D. The boy had to have his nose cut at last.

45. The boy should be taken to the seaside for a swim because ____.

A. he needed to learn to swim

B. the sea water would stop the bad smell of his nose.

C. the sea water would wash out the paper ball.

D. he needed a rest

判断题