某城市大量运输的需求的价格弹性估计为1.6，城市管理者问你，为了增加大量运输的收入，

（）是指监理单位的监理活动收入扣除直接成本、间接成本和各种税金之后的余额。

A．购货款

B．利润

C．总成本

D．投资额

防喷演习应遵循的原则是（）。

A.以司钻为中心

B.以队领导为中心

C.以班自为战

D.以队自为战

E.从实战出发

F.从演习出发

阅读理解。

     A young father was visiting an old neighbor. They were standing in the old man's garden, and talking

about children. The young man said, "How strict should parents be with their children?"

  The old man pointed to a string(绳子)between a big strong tree and a thin young one. "Please untie

(解开) that string," he said. The young man untied it, and the young tree bent (弯) over to one side.

"Now tie it again, please," said the old man, "but first pull the string tight so that the young tree is straight

again."

  The young man did so. Then the old man said, "There,it is the same with children. You must be strict

with them, but sometimes you must untie the string to know how they are getting on. If they are not yet

able to stand alone, you must tie the string tight again. But when you find that they are ready to stand

alone, you can take the string away."

1.The story is about____.  

A. how to take care of young trees    

B. how strict parents should be with their children

C. how the young father should get on with his old neighbor

D. how to tie and untie the string

2.The young man untied the string ____.

A. in order to throw it away          

B. so that both of the trees would grow straight

C. only to find that the thinner one bent over to one side

D. in order to let the old man teach him

 3.When can the string be taken away?  

A. When the old man has left                

B. After you have untied it

C. When the young man has untied it next time

D. When the young tree grows strong enough

4. At last the old man told the young man _____ .

A. that he should be strict with his children if they could not yet stand alone

B. that he should always be strict with his children    

C. that he should be hard on them

D. that he should tie his children until they are ready to stand alone

5. In the story the relation (关系) of the big strong tree to the thin one is like that of _____. 

A. the young father to the old neighbor                

B. parents to their children

C. the old neighbor to the children of the young father    

D. grown ups to their parents

为实现直流电动机反转通常采用什么办法？

影响传热膜系数的因素有很多，其中主要有（）。

A、流体的种类

B、流体的性质

C、流体的运动状态

D、流体的对流状况