不定式做状语主要表示目的、程度、结果、方式。

(1)in order to(do), so as to(do)结构引导目的状语，so as to不能置于句首。如：

(2)so…as to, such…as to, enough…to, too…to结构做程度状语。如：

The solution works only for couples who are self-employed, don’t have small children and get along well enough to spend most of their time together.

The vocabulary and grammatical differences between British and American English are so trivial and few as hardly to be noticed.

(3)不定式做结果状语只能出现在句子的末尾，表示不愉快的结果，有时用only加强语气。

常见的不定式动词有find, hear, see, be told, form, give, make, produce等。如：

Greatly agitated, I rushed to the apartment and tried the door, only to find it locked.

(4)not/never too… to, too… not to, but/only too…to, too ready/eager/apt/inclined to 表示肯定意义。如：

I am only too pleased to hear from you further. 能再听到你的消息，我太高兴了。