The writer thinks that over-achievers and under-achievers mainly differ in ________.

The effect of a volcanic eruption on climate may be to make it_________.

This passage is concerned with things that affect _________.

“You are too self-centered.It’s high time you （ ） that you are not the most important person in the world,” Edgar said to his boss angrily.

In some parks visitors are requested to keep （ ） the grass.

After （ ） seemed to be an endless wait, it was finally his turn to have the interview.

No sooner had I locked the door （ ） the telephone rang.

Jane hadn’t been to London before．（ ）had her husband．

There is no （ ） in applying for that job as you are not properly qualified.

To help readers understand how climate can change, the writer uses _________.

What does the author think a student should do if he has a boring teacher?

（ ） the price, it is a thousand times worth it.