问题 问答题 简答题

试说明四冲程发动机进气行程的工作情况?

答案

参考答案:

依靠飞轮惯性通过曲轴将活塞由上止点运行到下止点。活塞上方容积增大,形成一定真空度,进气门打开,排气门关闭。在大气压力作用下,空气从进气管道进入气缸,污塞移到下止点附近时,进气门关闭,进气行程结束。

阅读理解

阅读理解

     Since the pre-historic times, man has had an urge to satisfy his needs. Be it hunger, shelter or search for a mate, he has always controlled the situations to his advantage. Probably this might be the reason why we humans are the most developed of all living species on the earth. As we climbed the steps of development, we somehow left behind common sense and logical thinking -- we forgot that we have stopped thinking

ahead of time.

     If you are hungry, what do you do? Get a piece of your favorite meal and stay quiet. Just like your

stomach, even your mind is hungry. But it never lets you know, because you keep it busy thinking about

your dream lover, favorite star and many such things. So it silently began to care about your needs and

never let itself grow. When mind looses its freedom to grow, creativity gets a full stop. This might be the

reason why we all sometimes think "What happens next?", "Why can't I think?" "Why am I always given

the difficult problems?" Well, this is the result of using our brain for thinking of not-so-worthy things.

     Hunger of the mind can be actually satisfied through reading. Now why reading and not watching TV? Because reading has been the most educative tool used by us right from the childhood. Just like that to

develop other aspects of our life, we have to turn to reading. You have innumerable number of books in

this world which will answer all your "How to?" questions. The interesting part of the book is stored in your mind as a seed. Now this seed is unknowingly used by you in your future to develop new ideas. The same seed, if used many times, can help you link and relate a lot of things, of which you would have never

thought in your wildest dreams! This is nothing but creativity. More the number of books you read, your

mind will open up like never before.

1. What is the function of the first paragraph?

A. To show humans are the most developed.

B. To introduce the topic of the passage.

C. To indicate people have different needs to satisfy.

D. To explain why people need to read.

2. What does the author mean by saying "When mind looses its freedom to grow, creativity gets a full

stop."

A. When mind keeps growing, creativity fully stops.

B. When freedom is lost, creativity gets a full stop.

C. When mind stops growing, creativity fully stops.

D. When growing is lost, creativity gets a flail stop.

3. The paragraph following the passage is probably about ______.

A. how the pre-historic man feeds his mind

B. what other advantages reading brings

C. how to develop creativity

D. how to satisfy your mind by watching TV

4. The author tends to tell us ______.

A. reading can satisfy your all needs      

B. reading can result from creativity

C. reading can feed your mind            

D. reading can realize your dreams

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