问题 问答题 简答题

电机车控制器和自动开关采用哪种消弧方法?试述消弧原理。

答案

参考答案:

采用电磁吹弧和消弧罩降温消弧方法。

当触头分开产生电弧时,消弧线圈两端产生磁场仍然存在,则电弧处在磁场中间,这样电弧在磁场力作用下向外移动,电弧的根部离开静触头被推移到导弧角上,电弧被拉长进入消弧罩根部,使电弧迅速冷却而熄灭。

阅读理解

.

People often talk as if shyness is a disease or mental condition that can be cured. I prefer to think of it as an emotional disability. It’s something we are born with and something we carry with us in our entire lives. There are many people, however, who seem to be determined to find some way of doing away with their shyness. In my opinion, it’s a waste of time. I don’t mean that we should do nothing about it; quite the contrary, I think we need to separate the basic fact of our shyness from our ability to take part in a social environment.

Look at one of the most famous shy people, Johnny Carson. This man is painfully shy, yet for decades he made a living talking and associating(交往) with different people every night, in front of a national audience. Carson has never done away with his shyness, but he has successfully found a way to deal with it to the extent that he could be, not just a talk show host, but a legend(传奇) among talk show hosts. Look also at Sally Fields, who has recently admitted her problem with shyness. This is a woman who has appeared in many films, TV shows and interviews, yet in her early years she was so shy that she turned down a lunch invitation from Jane Fonda because she was terribly afraid of meeting her.

I guess that our shyness is there because each of us is born with some insecurity and this insecurity prevents us from reaching out to others the way people with a more open personality do. As we grow up, we allow our social skills to grow and develop. But we are still stuck in kindergarten or elementary school or wherever it was when our shyness took root in our soul.

67. In the author’s view, shyness can be explained as ________.

A. a disease that can be easily cured       B. a not very normal mental condition

C. an emotional disability               D. something we pick up after birth

68. The author believes it’s a waste of time to _________.

A. develop a healthy personality         B. talk with people as much as possible

C. study where shyness comes from      D. look for ways to do away with one’s shyness

69. Which of the following is TRUE of Johnny Carson?

A. He dared to speak in front of a national audience.

B. He did away with his shyness carefully.

C. He was described as a hero in some legend books.

D. He failed to become a good talk show host.

70. The underlined word “insecurity” in the third paragraph probably means “________”.

A. feeling safe     B. feeling supported    C. feeling afraid     D. feeling comfortable

多项选择题