9、过去完成时

John had learned some Chinese before he came to China. He found the book that he had lost.

By the end of last year， I had worked in this college for ten years.

no sooner………than， hardly(scarcely)……when(before)

We had no sooner reached home than it began to rain. No sooner had we reached home than it began to rain.

He had hardly entered the office when (before) the phone rang.

10、现在完成进行时(常跟for hours， since this morning等表示一段时间的状语连用)

They have been watching TV for two hours. He has been working on this essay since this morning.

11、时态呼应特殊规则

Kepler proved that the sun is the center of the solar system. 客观真理

I didn‘t go to the ball because I am not fond of dancing. 意义需要

被动语态

一般时态 进行时态 完成时态

现在 am

is written

are am

is being given

are has

been written

have

过去 was

were written was

were being given had been written

将来 shall

will be written shall

will have been written

过去将来 should

would be written should

would have been written