15：

why not do sth 为什么不做……呢？

why not go over your notebook？

为什么不复习一下笔记呢？

16：

It's time to do sth. 到做某事的时间了

It's time to clean the classroom.

该打扫教室了。

17：

sb. devote oneself/one's life to sth./doing.

致力于做某事

She devoted herself to teaching English.

她致力于教英语。

18：

It is/ was+被强调部分+that/who…

It is this boy who broke the window.

是这个男孩打破了窗户。

19：

I don’t think/believe/suppose/expect+that

从句否定前移

I don’t think he will win the game.

我认为他不会赢得比赛。

20：

would like to do 想要做某事

feel like doing 想要做某事

had better （not） do sth 最好（不）做某事

would rather do 宁愿做……

I would like to drink some water.

我想喝水。

21：

It is no use doing sth. 做某事没有用处

It is no use watching too much TV.

看太多电视是没用的。

22：

主语+have no idea+从句 不知道……

I have no idea when he will come back.

我不知道他什么时候回来。

23：

no matter when/where/what/who/whether/how...

无论......

No matter who you are， you must obey the law.

无论你是谁，都必须遵守法律。

24：

used to do 过去常常做某事

be used to doing 习惯于做某事

I used to make a joke on him.

我过去常常开他玩笑。

I have been used to getting up early.

我已经习惯了早起。

25：

It is possible/probable/likely that…

可能……

It’s possible but not likely/probable that he’ll come here next month.

他下月有可能来这里，但是不是很肯定。