选择与句中画线部分意思相同或相近的词或短语。

1. What's wrong with the old man?

A. the thing

B. the trouble

C. matter

2. The child is not old enough to do the work.

A. so young

B. quite young

C. too young

3. If you don't work hard on subjects, you will fail the test.

A. pass the exams

B. miss the exams

C. not pass the exams

4. Everything will be free  in the future.

A.You needn't pay for it

B. It's very cheap

C. It's very expensive

5. They enjoyed themselves yesterday.

A. have a good time

B. had a great time

C. has fun

油气井井口装置可以保证各项井下作业施工和进行测压、清蜡等油气井（）生产等日常管理。

A、平时

B、特殊

C、日常

D、重点