高中英语语法讲解不定式

高中英语语法讲解不定式

（The Infinitive）

定义：动词不定式是非谓语动词的一种，它没有人称和数的变化，在句子中不能独立作谓语，但它仍保持动词的特点，既可以有自己的宾语和状语。 E.g. He wants his students to read the book aloud.

A．基本形式

1不定式的构成（以动词do为例）

主动形式被动形式

一般式to do to be done

完成式to have done to have been done

进行式to be doing 无

完成进行式to have been doing 无

2不定式的意义

不定式的一般式(to do )

一般式表示的动作或状态，发生在谓语动词表示的动作或状态的同时或之后。当不定式的逻辑主语是这个不定式所表示的动作的承受者时,不定式一般要用被动式(to be done).

eg: My wish is to become a doctor

He seemed to be tired.

She stopped to have a rest.

The building to be finished next month is for our teachers.

I am going to Beijing, I have something to take to my parents, do you have something to

be taken to your parents?

不定式的进行式（to be doing）

如果谓语表示的动作(情况)发生时, 不定式表示动作正在进行,这时候不定式就要用进行式.

eg: They are said to be building another bridge across the street.

They seemed to be talking about something important.

When I went to his home, he happened to be traveling around the world.

I’m glad to be working with you.

不定式的完成式 (to have done)

如果不定式所表示的动作或状态发生在谓语动词所表示动作或状态之前，就用完成式；若是在此基础上的被动含义，就用完成被动式( to have been done).

eg:He is said to have written a novel about the Long March.

He thought it a pity not to have invited us.

The assistant seemed to have been fired.

He is said to have been taught French when he was a child.

Einstein is said to have built up his theory when he was in his twenties.

不定式的完成进行式(to have been doing)

如果不定式的动作是在谓语所表示的时间之前一直在进行或有可能继续进行的动作，就要用完成进行式.

eg: They are said to have been collecting folk songs in Xinjiang.

We’re happy to have been working with the experts all the month.

B. 用法：

动词不定式具有名词、形容词和副词的特征。因此在句中可以做主语、表语、宾语、宾语补足语、定语和状语。

一、不定式做主语：

不定式做主语一般表示具体的某次动作。===动名词doing 表示习惯的，经常的动作。

eg: To finish the building in a month is difficult.

To do such things is foolish.

To see is to believe. (对等)

To make a new dress takes her a lot of time.

注意：1)不定式作主语时,谓语用单数

2) it形式主语。当主语较长，谓语较短时，常用it做形式主语，而将不定式放到谓语的后面。常用于下列结构中：

(1)It is/was +adj.+(of sb.) to do…

(2)It is +adj.+(for sb.)+to do…

It is easy / difficult / hard / foolish / unwise / right / wrong / unnecessary…

(3) It is +a/an +名词+ to do...

It is a pity / a pleasure / a pleasant thing / one’s duty / an honor / a shame / a crime / no easy job… to do

(4)It takes(sb.) some time / courage / patience …to do…

(5)It requires courage / patience / hard work… to do…

*注意: probable 和 possible 均可作表语，但possible可以用不定式作真实主语，而probable 不能用不定式作真实主语。

It is probable for him to come to the meeting.(错）

It is possible for him to come to the meeting.

It is possible / probable that he will come to the meeting.

3）主系表结构To see is to believe.

二、不定式做表语

主语多用aim duty hope idea intention plan job suggestion wish purpose task 等抽象名词或以 what 引导的名词性从句表示，后面的不定式说明其内容, 不定式作表语常表示将来的动作或状态。

eg: My idea is to climb the mountain from the north.

What I would suggest is to start work at once.

My wish is to be a scientist.

The main thing is to keep our room clean.

注意：1不定式to let, to blame, to rent,to hire做表语,主动表被动. The house is to let.