问题 问答题 简答题

煤粉有哪些主要特性?

答案

参考答案:

⑴煤粉具有极大的表面积。⑵煤粉具有良好的流动性。⑶煤粉与空气的混合物容易分离。⑷煤粉与氧接触会发生氧化。⑸煤粉的爆炸性。

阅读理解

阅读下面短文,根据所给语境,按要求完成下列各题。

    The first walk into outer space was taken by a Soviet astronaut. Astronaut Zhai Zhigang became the first

Chinese to walk in space on September 27,2008. It showed that it was quite safe for a man to be outside the

spaceship for a certain period of time. But to walk in space, astronauts have to meet with many kinds of

difficulties and dangers.

    The spaceship goes round the earth at an altitude (海拔高度) of about 200 kilometers above its surface. At

such altitudes there is no atmosphere which prtects the life on the earth. The conditions of outer space are very

harmful to man.

    The boiling point of liquids (液体) goes down with pressure. But pressure outside the spaceship is nearly

zero. In such conditions the decompression (减压) of the spacesuit may cause the boiling of the blood and quick

death. There is radiation from space and it is harmful.

    Breathing problems in space can be solved with the help of the spacesuit. Another problem is heat. Man gives

off heat in the course (过程) of his activity, and the harder the labor (劳动) is, the greater the amount (总量) of

heat is. In space unless special measures are taken, the heat inside the spacesuit would make the conditions

difficult.

1. 根据处完成下面的句子。(每空一词)

    Zhai Zhigang became the first Chinese astronaut _______  _______ in space on September 27, 2008.

2. 根据短文内容,完成下面的句子。(每空一词)

    The altitude is so _______ that there is no atmosphere which protects the life on the earth. At the same time,

    the astronauts usually meet with some problems, such as _______ problem, radiation problem, breathing

    problem, heat problem and so on.

3. 将画线句子翻译成汉语。

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填空题