高二英语语法:高二英语语法精讲 不定式

不定式既具有动词的一些特征，又具有名词，形容词和副词的句法功能

否定式：not +不定式

不定式的时态

一般说来，不定式一般式表示的动作有时与限定动词表示的动作同时发生，也有时发生在限定动词表示的动作之后。如：

Who heard him say that?

He seems to know this.

I hope to see you again.

不定式进行式表示动作正在进行，通常与限定动词表示的动作同时发生，如：

They are said to be building another bridge across the river.

I happened to be going that way too.

不定式完成式表示的动作发生在限定动词表示的动作之前，如：

I am sorry to have given you so much trouble.

I am glad to have seen your mother.

不定式的句法功能

(1)作主语

To talk with him is a great pleasure.

不定式短语作主语时，为了保持句子的平衡，往往以it作形式主语，而把不定式短语置于谓语动词之后，如：

It’s nice to hear your voice.

(2)作表语

Her wish is to become an artist.

(3)作宾语

常用于及物动词: want , hope, wish, like, need, hate, offer, prefer, begin, start, attempt, decide, determine, expect, promise, pretend, refuse ,afford, manage, help等之后，如：

You should continue to learn as long as you live.

注1：如果作宾语的不定式又有自己的补语，则须用先行词it 作形式宾语，而将真正的宾语不定式后置，如：

They found it impossible to get everything ready in time.

注2：不定式一般不能作介词的宾语，只有在极少数介词如:but, except等后边才行。此时不定式可以带to或不带to,如：

In very cold winter weather a cold-blooded animal has no choice but to lie down and sleep.

There was nothing left to do but clean the windows.(前边有do, to 省略)

但“疑问词+不定式”结构可以作介词的宾语，如：

I have no idea about what to do next.