问题 问答题 简答题

简述怎样对道岔进行密贴检查?

答案

参考答案:

道岔尖轨密贴良好、无反弹,各牵引点密贴调整适度,扳动平顺。密贴段牵引点处尖轨和基本轨,心轨和翼轨有4mm及其以上间隙时,道岔不能锁闭和接通道岔表示。两牵引点间尖轨和基本轨间有5mm及其以上间隙时,不能接通道岔表示。

阅读理解

Reading comprehension.

     Kangaroos live among the tall grasses in central Australia.During the day, they sleep in the shade (阴影).

They usually search diligently (勤劳地) for green grass or leaves in the evening.   

     Some kangaroos can grow to a height of two metres while others are rather short.They have long tails

which help them keep their balance (平衡).Their front legs are short and their front feet are small. But they

have big hind (后面的) feet act like springs (弹簧). Because of them, the kangaroos can jump very far.The

aborigines (土著人) hunt kangaroos for food with the help of large dogs and sometimes with spears (矛).

It is difficult to catch kangaroos because they fight back using their feet and strong tails.   

      Kangaroos have good hearing, keen (敏锐的) sight and sharp sense of smell.They are aware (意识到的)

when an enemy (敌人) appears at a distance.The males warn the others in the herd (兽群) by stamping their

hind legs.

Write the key words according to the passage above. (根据上面的短文写出关键词)

1. Kangaroos live in ____ ____.   

2. During the ____, they ____ in the shade.   

3. The kangaroos usually look for green ____ or ____ in the evening.   

4. Some large kangaroos are ____ ____ tall.   

5. The kangaroos'front legs are ____ and their front feet are ____.   

6. Because of their ____ ____, the kangaroos can jump very far.   

7. The aborigines hunt kangaroos for food with the help of large ____ and ____.   

8. It is ____ to catch kangaroos because they fight back using their feet and ____ tails.   

9. Kangaroos have ____ hearing, ____ sight and ____ sense of smell.   

10. The ____ warn the others in the herd by ____ their hind legs.

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