离心泵启动后打不上液体可能因为叶轮或键损坏，或泵口环磨损严重。

We live in the computer age. People use computers to do much of their work. But few people know how to look after them. Remember the following when you use your computer:

① Keep your computer in a cool ,dry room. Too much or too little heat is bad for computers. Damp (潮湿) is also bad for them.

② Do not let people smoke near your computer. Smoke of all kinds is very bad for many parts of a computer.

③ Do not eat or drink when you are near your computer. Pieces of food and a little water in the keyboard are also bad for a computer.

小题1:Computers can ____ people to do a lot of work.

A. help      B. make        C. use

小题2:Few people know how to_____ their computers.

A. look for   B. take care of   C. look at

小题3:A computer works well at a temperature of _____.

A. 0℃       B. 35℃        C. 20℃

小题4:Is smoking good or bad for many parts of a computer?

A. good      B. bad         C. I don’t know.

小题5:A dirty screen or a very bright screen is ______ for your eyes.

A. helpful     B. good        C. bad

读世界某植被类型分布图，回答下列各题。 

小题1:上图中，图例1和图例2所示的植被类型都是

A．森林

B．草原

C．沼泽

D．荒漠小题2:关于该植被的说法，正确的是

A．图例1代表的植被分布最广的是非洲大陆

B．我国内蒙古地区该植被类型与图例2一致

C．图例1代表的植被分布多为非地带性规律

D．图例2代表的植被分布符合从赤道向两极的地域分异规律

压力加工的操作工序中，工序名称比较多，属于自由锻工序的是（），属于板料冲压工序的是（）。

A.镦粗、拔长、冲孔、弯曲；

B.拉深、弯曲、冲孔、翻边；

C.镦粗、拔长、冲孔、轧制；

D.拔长、镦粗、挤压、翻边。

电力系统由于小扰动产生的低频振荡，振荡频率一般为( )。

A．0～0.2Hz；
B．0.2～2.5Hz；
C．5～10Hz；
D．10～20Hz。

_____________的《春风秋雨》、《白云珠海》、《山长水远》被称为“虾球传”三部曲。( )

A．黄谷柳

B．叶君健

C．李准

D．刘心武