简述压缩空气系统投运步骤.

短文填空：在下面短文的每个空白处填入适当的词，每空只填一词，首字母已给出。

     Students learn their lessons in class. They sit in the classroom and (1)l______ to the teacher. This is a way

of learning. Is this the (2)o______ way for students to learn? Of course not. There is another way to learn.

That is students can teach themselves. For (3)e______, if you cannot remember something when you are doing

your homework, what will you do? You can look at your books to (4)f______ the answers.

     How to teach yourself? The first thing you must do is reading. Read something you are (5)i______ in, or

you have to read. The second is that you must ask yourself questions. A clever student is usually (6)g______

at asking questions. The third is to answer the questions yourself by (7)w______ hard, by reading books, and

sometimes by asking (8)o______ people. There are the ways of teaching yourself. If you keep doing (9)l______

these for a long time, You are sure to have great (10)s______ in your study.

关于变更合同价款的说法，错误的是( )。

A．合同中已有适用于变更的价格，按合同已有的价格变更价款
B．合同中只有类似于变更工程的价格，可以参照类似价格变更合同价款
C．合同中没有适用或类似于变更工程的价格，由承包人或发包人提出适当的变更价格，经对方确认后执行
D．合同中只有类似于变更工程的价格，可以按市场价格与类似于变更工程的价格孰低进行确认

咳嗽肝火犯肺证的主症特点是（）

A.咳声重浊，痰多，痰出咳平，痰黏腻色白

B.干咳无痰，咽喉干痛，唇鼻干燥

C.干咳，咳声短促，痰中带血丝

D.咳嗽痰多，质稠色黄

E.咳嗽呈阵发性，咽干口苦，胸胁胀痛

为保证卷绕速度恒定，可以利用横动速度进行反馈控制锭子轴转速。

化学分析包括（）分析、（）分析和定量分析。