在临近零转速时，电制动力矩急剧下降，因此设置机械制动是必要的（）

试述支气管扩张的手术适应证。

阅读理解

     Do you get angry when your friends sing loudly? Or when your best friend does not wait for you

after school?

     If you do, you need to control(控制) your feelings and stop getting angry so easily. Getting angry 

easily can make you lose friends.

     Gary Egeberg, an American high school teacher, wrote My Feelings are Just Like Wild Animals

to help you control your feelings. It tells teens how to stay cool when bad things happen to them.

The book says that getting angry only makes problems worse. It can not make them better. "Getting

angry is not a natural way to act", the book says. It is just a bad habit, like smoking. The book says

you can control your anger easily, and all you have to do is to tell yourself not to be angry.

     When a baby falls over, it cries only when people are watching it. Like a baby, you can only

get angry if you are sure it is the right thing to do.

     The book gives many suggestions to help you if you get angry easily. Here are the top three.

     ①Keep a record. Every time you get angry, write down why you are angry. Look at it later

and you will see you get angry too easily.

     ②Ask your friends to stop talking to you when you get angry. This will teach you not to be

angry.

     ③Do something different. When you get angry, walk away from the problem and go

somewhere else. Try to laugh!

1.The writer wants to tell us ____.

A. not to get angry easily

B. to work hard at school

C. to do more exercises

D. to help each other

2. The writer thinks that if you get angry easily you will ____.

A. get ill very easily

B. lose your friends

C. put on weight easily

D. eat less

3. My Feelings are Just Like Wild Animals is a ____.

A. story

B. book

C. picture

D. film

4. My Feelings are Just Like Wild Animals mainly tells us ____.

A. what to read

B. how to read

C. how to stay cool

D. how to learn English well

5. In the fourth paragraph, the underlined word "it" refers to(指的是)____.

A. the book

B. anger

C. habit

D. the baby

狼体内有a种蛋白质，20种氨基酸，兔体内有b种蛋白质，20种氨基酸。狼捕食兔后，狼的一个细胞中含有蛋白质种类及氨基酸种类最可能是 [ ]

A．a+b，40

B．a，20

C．大于a，20

D．小于a，20

氮元素是构成生物体的最主要元素之一，在动植物生命活动中起着重要作用。下图是自然界中氮循环以及有机物在生物体内代谢的部分过程示意图，请分析回答：

土壤中能完成②③过程的生物不多，这种生物属于生态系统中的（）。

平衡状态