问题 问答题 简答题

轮胎的作用及分类?

答案

参考答案:

A.按轮胎的构造不同分为有内胎和无内胎的两种。

B.按轮胎的空气压力大小分为高压胎和低压胎两种。

C.按胎体结构分斜交轮胎和子午线轮胎两种。斜交轮胎,胎体的帘线方向与轮胎的中心线(圆周方向)方向成35度角。子午线轮胎,胎体的帘线方向与轮胎的中心线方向成90度角。帘线的这种分布情况很像地球上的子午线,故称子午线轮胎。

D.按照胎面花纹分为普通花纹轮胎,混合花纹轮胎和越野花纹轮胎。轮胎的作用:承受载荷产生驱动力与制动力缓冲和吸震改变汽车行驶方向

阅读理解

阅读理解。

     People believe that climbing can do good to health. Where can you learn the skill of climbing then? If you

think that you have to go to the mountains to learn how to climb, you're wrong. Many Americans are learning

to climb in city gyms (体育馆). Here, people are learning on climbing. The climbing wall goes straight up and

small holding places for hands and feet.

     How do people climb the wall? To climb, you need special shoes and (保护带) around your chest to hold

you. There are ropes (绳索) tied to your. The ropes hold you in place so that you don't fall. A beginner's wall

is usually about 15 feet high, and you climb straight up. There are small pieces of metal that stick out for you

to stand on and hold on to. Sometimes it's easy to see the new piece of metal. Sometimes, it's not. The most

difficult is an your fear. It's normal for humans to be afraid of falling, so it's difficult not to feel fear. But when

you move away from the wall, the and the ropes hold you, and you begin to feel safe. You move slowly until

you reach the top.

     Climbing attracts people because it's good exercise for almost everyone. You use your whole body,

especially your arms and legs. This sport gives your body a complete workout. When you climb, both your

mind and your body can become stronger.

1. What can we infer from the passage?

A. People are fairly interested in climbing nowadays.

B. It is impossible to build up one's body by climbing.

C. People can only learn the skill of climbing outdoors.

D. It is always easy to see holding places in climbing.

2. The most difficult thing to do in wall climbing is _____.

A. to tie ropes to your

B. to control your fear

C. to move away from the wall

D. to climb straight up

3. The word "workout" underlined in the last paragraph most probably means _____.

A. settlement

B. exercise

C. excitement

D. tiredness

4. Why does the author write this passage?

A. To tell people where to find gyms.

B. To prove the basic need for climbing.

C. To encourage people to climb mountains.

D. introduce the sport of wall climbing.

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