非谓语动词-不定式学习笔记（难点）

1,概述：动词不定式和它的宾语、状语或表语一起构成不定式短语。不定式或不定式短语具有名词、形容词、副词的性质，因而可以在句中作主语、宾语、表语、定语和状语。在不定式符号to前加上not 构成不定式的否定式。

2,动词不定式也可以做介词but,except, save（除…以外）的宾语，但在词组can not but, cannot help but, do nothing but后面，接不带to的不定式。在except,save后面可带to也可不带to.

She does nothing but cry all day.

She did nothing except play all day long.

There is nothing for it but to wait for anopportunity.

3,动词不定式做宾语补足语时

在make(使)，let（让），have(使，叫)等使役动词后，在see，watch, look at, behold, observe, perceive, feel, hear, listen to,notice等表示感官的动词后以及在know, please 等后面省去动词不定式符号“to”.在动词find和help后可省也可不省。

有些动词如consider, prove, think, know, feel, suppose, discover, imagine, find等也可跟“宾语+to be”的形式，使用中应注意。

We found him (to be) dishonest.

4,做主语补足语

如果把不定式做宾语补足语的句中的谓语由主动状态改为被动状态，则原来做宾语补足语的不定式变成饿了主语补足语。此时原来省去的“to”一般不能再省去了。

Plastics are found to be good insulators.

Water power can be made to produce electricity.

5.做状语

表目的、结果、原因等。

In order to, to, so as to,等

The temperature is so high as to changewater into steam.

用在easy, difficult, hard, heavy, good 等形容词作表语的系表结构中的形容词后，不定式要用主动式。

This question is hard to answer.

Electricity is easy to transmit over long distance.

比较：

Water is known to be composed of hydrogen and oxygen.

相对来说，动词不定式用作状语的情况搭配较多也较复杂。如：

She sat at the table, collar off, head down, and pen in position, ready to begin the long letter.

Rong Hong returned only to find a poverty-stricken country under a corrupt government.

6．动词不定式的逻辑主语。

一般：for +名词（代词）+不定式短语。

但是，如果句中的形容词既指行为的性质又指行为的人，则用of 引出这一结构。

It’s very kind of you to send us so manybooks.

It’s difficult for me to accomplish this work alone.

The development of the rocket makes it possible for a man to enter a space.

7.动词不定式符号to后动词的省略

不定式用在并列句和复合句中，省去后面一个相同的动词，只留下to.

He refused to take a rest, though we had asked him to.

He will begin his research work ASAP，If he is allowed to.