简述地质和生产对矿井煤层自燃的影响。

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问题:

简述地质和生产对矿井煤层自燃的影响。

考点:煤矿应知应会煤矿安全生产应知应会煤矿安全生产应知应会题库
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任务型阅读.

      Lots of people like diving into water, because they can explore the underwater world. But there is

another kind of diving.  Some people dive into the sky! This is really a very exciting sport. A skydiver

goes high up in the air on a plane. Then he jumps off the plane and floats(飘)in the air with the help of 

a parachute(降落伞).A parachute is like a huge umbrella.It is put on the back of the skydiver. When

the skydiver reaches a certain height, he will pull a string(细绳)and the parachute will open up in seconds

and carry him gently(轻轻地)down to the ground.  Skydivers like doing a lot of fascinate tricks in the

air.  After jumping off the plane one after another, they will try to stay in the air and hold each other's

hands. |They can form different shapes. Is it safe to do skydiving? Yes, as long as we receive right training. But sometimes, accidents do happen. In Canada, two skydivers were killed in 1991 when they jumped

off  the plane.  Because their parachutes got tied up with each other, the parachutes couldn't open up and

both crashed down and died.

1. Why do people like diving into water?

                                                                      

2. How does a skydiver go up into the sky?

                                                                      

3. What does a parachute look like?

                                                                      

4. Where does a skydiver put his parachute?

                                                                      

5. Why were two skydivers killed in Canada?

                                                                      

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At last, Lucy make the baby ____ and the baby began to laugh.

A.stop crying

B.to stop crying

C.stop to cry

D.to stop to cry

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设有关系R(A,B,C,D,E),A、B、C、D、E都不可再分,则R一定属于( )。

A.1NF

B.2NF

C.3NF

D.以上3个选项都有可能

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合成系统爆炸着火或气体、液氨大量泄漏时如何处理?

题型:问答题 简答题

遗传物质的主要载体是()。

A、线粒体

B、中心体

C、染色体

D、核糖体

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