不与动词不定式连用是作为介词的标准之一 ，是符合英语的一般规律的。但是，有几个介词属于例外： besides ， except ， but ， save 等等。

They did nothing but complain .

She can do everything except cook .

像 will , willingness , attempt , promise  , decision ,  determination , inclination , invitation , proposal , refusal , resolution 这样一些抽象名词，常常需要用动词不定式来使其内容具体化。这样的动词不定式应分析为同位语。

Any attempt to leave early is against regulations .

We gratefully accepted his promise to help us .

She lost her will to live ...

He made a firm resolution to give up smoking .

His refusal to play the game provoked the other boys .

If we go on polluting the world , it won't be fit for us to live in .

用作形容词的fit ， 除了接for 短语之外， 还可以接动词不定式。 动词不定式应分析为形容词fit的补足语。但有三种不同 的情形：

A. 句子的主语是动词不定式的逻辑主语

 She's not fit to live by herself .

B. 句子的主语是动词不定式的逻辑宾语

These shoes are not fit to wear .

C. 句子的主语是动词不定式中介词的宾语

The weather is not fit (suitable ) to go out in .