问题 问答题 简答题

为什么直顶式液压电梯井道上端的顶部间距可以比相同速度的曳引电梯的小?

答案

参考答案:

电梯的顶部间距,是从上行电梯在动力中止后,由于惯性还要向上移动一定的距离来考虑的。由于直顶式轿厢与柱塞是连在一起的,所以动力中止后,向上移动的阻力比曳引电梯大得多,所以距离可以比曳引电梯小。

阅读理解

Changsha,

Hunan Province

May 6, 2010

Dear editor,

Under China’s current (现在的) educational system, there are those who do nothing but study. They of course are thought to be model students.

But I feel that there is another type of student who, perhaps not as diligent (勤奋的) as the first type, uses his time more efficiently and achieves a lot academically.

Last year, a classmate of mine was accepted by a top university. It surprised all of us. It was because, unlike most of us, he didn’t spend too much of his time studying.

When I asked him the secret of his success, he said that the key was properly and scientifically arranging his time.

“ I spent a lot of time keeping fit and as a result, I was able to better concentrate (集中) on my class work.”

The moral (教训) of the story is: it isn’t necessary to sit at your desk all day long to get high academic (学术) grades.

Yours,

Zhang Zishu

小题1:What does the letter-writer (a reader) think leads to the fact that many students do nothing but study?

A.The present educational system.

B.People’s old ideas.

C.The teaching methods.

D.The parents of these students.小题2:It seems that this reader thinks        .

A.the first type of student is our model

B.the second type of students is our model

C.both types of students are worth learning from

D.neither of the two types of students are good小题3:The reader wrote the letter in order to        .

A.call on us to work even harder

B.cause people to think about how to study more efficiently (有效地)

C.advise people to do research into his classmate’s success

D.criticize (批评) China’s educational system小题4:What would be the best to stand for (代表) the letter-writer’s opinion?

A.Secret of success.

B.China’s educational system needs changing.

C.Work while you work and play while you play.

D.Keep fit first.

多项选择题