英语动词不定式语法知识点归纳总结

英语动词不定式语法知识点归纳总结

动词不定式

考向一不定式的作用

1. 作主语：不定式作主语时，谓语用单数。往往用it 作形式主语，把不定式放在谓语后面。It took us two hours to finish the job.

2. 作宾语（1）动词+不定式。

☞He managed to escape from the fire.

☞I find it hard to get along with him. （it 作形式宾语）

（2）动词+疑问词+to，＂特殊疑问句+不定式＂相当于名词，作宾语。

☞I don’t know what to do next/ how to do it next.

不定式短语作宾语时，如果还带有宾语补足语，往往把不定式短语放在宾语补足语之后，用it 作形式宾语。

☞I find it necessary to learn a foreign language.

3. 作宾语补足语

（1）动词+宾语+不定式（to do ）。

☞He warned me to be careful.

注意：可以用动词不定式作宾补的动词有：ask，tell，order，want，get，would like，like，advise，invite，allowhelp，wish，warn，expect，would prefer，encourage。

（2）表见解、看法的动词结构可为：动词+宾语+ to be 的不定式结构。

☞We consider Tom to be one of the best students in our class.

The book is believed to be useful.（被动语态）

（3）There +不定式。

We didn’t expect there to be so many people there. 我们没料到会有那么多人在那里。

（4）在动词feel （一感），hear, listen to（二听），have, let, make（三让），notice, see, watch, observe, look at（五看）(即：吾看三室两厅一感觉)等后面的补足语中，不定式不带to，但变为被动语态后，必须带to。

☞They saw the boy fall off the tree.

（5）help后面作宾语补足语的不定式可以带to，也可以不带to。

☞I often help him (to) clean the room.

☞I helped him (to) find his things.

4. 作定语

不定式作定语，修饰名词或代词，不定式和它所修饰的名词之间有逻辑上的主谓关系、动状关系、同位关系或动宾关系。不定式通常要放在这些被修饰的词后。

I have a lot of work to do.（动宾关系）

He is looking for a room to live in.（动状关系）

He is the first person to think of the idea.（主谓关系）

He has got a chance to go abroad.（同位关系）

5. 作状语

作状语，表示目的、结果、原因等，有时还有一些固定搭配的不定式短语，如in order to，so as to，so... as to，such...as to，enough to，too...to等。

（1）作目的状语，just to，only to（仅仅为了），in order to，so as to，so(such)... as to...（如此……以便……）

☞He ran so fast as to catch the first bus. 他飞快地跑以便赶上第一班车。

（2）作结果状语，表事先没有预料到的，要放在句子后面。

☞He hurried to the post office only to find it was closed.

（3）作原因状语。

☞We were very excited to hear the news.

（4）作条件状语。

☞To turn to the left, you could find a post office.

6. 作表语

不定式可放在be动词后面，构成表语。

☞The question is how to put it into practice.

考向二不定式的时态和语态

1. 不定式的时态

（1）现在时：有时与谓语动词表示的动作同时发生，有时发生在谓语动词的动作之后。☞He seems to know this.

（2）完成时：表示的动作发生在谓语动词表示的动作之前。

☞I’m sorry to have given you so much trouble.

☞He seems to have caught a cold.

（3）进行时：表示动作正在进行，与谓语动词表示的动作同时发生。

☞He seems to be eating something.

（4）完成进行时：表示动作从过去某个时间开始，一直延续到现在，并有可能持续下去。☞She is known to have been working on the problem for many years.

2. 不定式的语态

当不定式的逻辑主语是其动作的承受者时，就用被动式。

He was seen to enter the hall.

考向三省to 的动词不定式

一、使役动词后省略to的情况

在let, make, have等使役动词后用作宾语补足语的不定式必须省略to。如：

☞My mother wouldn’t let me go to the film. 我妈妈不会让我去看电影的。

☞I don’t like milk, but mother made me drink it. 我不喜欢牛奶，可是母亲强迫我喝。