1）目的狀語

常用結構為to do ， only to do（僅僅為了）， in order to do，so as to do，so（such）… as to…（如此…以便…）。例如：

He ran so fast as to catch the first bus.他飛快地跑以便趕上第一班車。

I come here only to say good-bye to you.我來僅僅是向你告別。

2）作結果狀語，可以表示沒有預料到的或事與愿違的結果，不定式要放在句子后面。

I awoke to find my truck gone. 我醒來發(fā)現箱子不見了。

He searched the room only to find nothing. 他搜索了房間，沒發(fā)現什么。

3） 表原因

I’m glad to see you. 見到你很高興。

She wept to see the sight. 她一看到這情形就哭了。

4）表示理由和條件

He must be a fool to say so.

You will do well to speak more carefully.