动词不定式讲解

动词不定式的用法

概念：

动词不定式由to+动词原形构成。这里的to是不定式标志，没有词义。不定式具有名词、形容词或副词的某些语法功能，又有动词的时态和语态的特点及作用。可以做主语、宾语、宾语补足语、表语、定语、状语。

一、作主语

动词不定式作主语时，句子的谓语动词常用单数，其位置有以下两种：

(1)把不定式置于句首。如：

To get there by bike will take us half an hour.

(2)用it作形式主语，把真正的主语不定式置于句后，常用于下列句式中。如：

①It＋be＋名词＋to do

It's our duty to take good care of the old.

②It takes sb+some time+to do

How long did it take you to finish the work

③It＋be＋形容词＋for sb＋to do

It is difficult for us to finish writing the composition in a quarter of an hour.

在句型③中，常用表示客观情况的形容词，如：

easy, difficult, hard, important, possible, impossible, comfortable, necessary, better;

the first, the next, the last, the best, too much, too little, not enough

④It＋be＋形容词＋of sb＋to do

It is stupid of you to write down everything the teacher says.

在句型④中，常用

careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise rude, clever, foolish, thoughtful, thoughtless（欠考虑的；不考虑的）, brave, considerate(考虑周到的), selfish(自私的)等表示赞扬或批评的词。在不定式前的sb，可看作其逻辑主语。这一句式有时相当于Sb is＋形容词＋to do句式，如：It's kind of you to help me with my English.=You are kind to help me with my English.

⑤It seems(appears)＋形容词＋to do

It seemed impossible to save money.

It seemed selfish of him not to give them anything. 他不给他们任何东西，这显得太自私了。

注意：1) 其他系动词如，look，appear等也可用于此句型

2) 不定式作为句子主语时，动词用单数形式。

3) 当不定式作主语的句子中又有一个不定式作表语时，不能用It is… to…的句

型

对应性：To see is to believe. 百闻不如一见。

二、作宾语

1) 以下动词后，只能跟不定式作宾语

afford （付得起），agree（同意），aim(力求做到), appear（显得），arrange（安排），ask（要求），attempt （试图），care（想要），choose（决定），claim（声称），condescend （屈尊），consent（准许），decide（决定），demand（要求），determine（决心），endeavor （竭力），expect（期待），fail（未履行），help（帮助），hesitate（犹豫），hope（希望），learn（学会），manage（设法），neglect（疏忽），offer（主动提出），plan（计划），prepare （准备），pretend（假装），proceed（接着做），promise（答应），prove（证明），refuse （拒绝），resolve（解决），seem（觉得好像），swear（发誓），tend（往往会），threaten （威胁），undertake（承诺），volunteer（自愿做），vow（发誓），want（想要），wish（希

望）

举例：

The driver failed to see the other car in time.

司机没能及时看见另一辆车。

I happen to know the answer to your question.

我碰巧知道你那道问题的答案。

2）动词+疑问词+ 不定式

decide, know, consider forget, learn, remember, show, understand, see, wonder, hear, find out, explain, tell

Please show us how to do that. 请演示给我们如何去做。

There are so many kinds of tape-recorders on sale that I can't make up my mind which to buy.有这么多的录音机，我都拿不定主意买哪一种。

注意:疑问词带不定式在句中作主语时，谓语动词用单数。

The question is how to put it into practice.

问题是怎样把它付诸实施。

3)当复合宾语中的宾语是不定式时，先用形式宾语it代替不定式，把不定式置于补语之

后，即：主语＋动词＋it＋补语＋to do句式。如：

We think it quite important for us to learn a foreign language well.

He feels it his duty to help the poor.

I find it difficult to learn English well.

三、作补语

1) 动词+宾语+不定式(to do)

advise allow believe cause challenge compel（强迫, 使不得不）declare encourage forbid force find hire induce（引诱, 劝导） instruct（命令, 指示）invite like order permit persuade remind request require select send suppose tell train urge（催促，鼓励）

例句：

a. Father will not allow us to play on the street.

父亲不让我们在街上玩耍。

b. We believe him to be guilty.

我们相信他是有罪的。

find 的特殊用法：

find 后可用分词做宾补，或先加形式宾语，再加形容词，最后加带to 的动词不定式。find 后也可带一个从句。此类动词还有get，have。

I found him lying on the ground.

I found it important to learn.

I found that to learn English is important.

典型例题:

The next morning she found the man ___ in bed，dead.

A. lying

B. lie

C. lay

D. laying

答案：A. find的宾语后面，用分词或分词短语，起宾语补足语作用。现在分词表达主动，也表达正在进行，过去分词表达被动。

lie: 躺过去式 lay,过去分词 lain , 现在分词 lying;

lie: 说谎过去式 lied,过去分词 lied , 现在分词 lying;

lay:安放过去式 laid,过去分词 laid, 现在分词 laying;

2) to + be 的不定式结构，作补语的动词。

Acknowledge ?承认, 供认, believe, consider, think, declare(声称),

discover, fancy(设想), feel，find, guess, judge, imagine, know, prove, see(理解), show, suppose, take(以为), understand

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

我们认为汤姆是班上最好的学生之一。

3) to be +形容词

Seem, appear, be said, be supposed, be believed, be thought, be known, be reported, hope, wish, desire, want, plan, expect, mean…

The book is believed to be uninteresting.

It is believed that…

人们认为这本书没什么意思。

有些动词需用as 短语做补语，如regard, think believe, take, consider.

We regard Tom as our best teacher. 我们认为汤姆是我们最好的老师。

Mary took him as her father . 玛丽把他当作自己的父亲。

四、作表语

不定式作表语表示具体动作或将来动作；动名词作表语表示抽象的一般行为。

①To be kind to the enemy is to be cruel to the people.

②My chief purpose is to point out the difficulties of the matter.

③What I would suggest is to put off the meeting.

当主语和表语都是不定式时，其含义一是条件，一是结果（例①）。当主语是aim,duty,hope,idea,mista ke,plan,purpose,suggestion等为中心词的名词词组（例②）时，或以what引导的名词性分句（例③），不定式说明主语的内容。

④Our work is serving the people.

⑤What he likes is taking a walk after supper.

⑥The story told by Mr Wang is interesting.

④⑤句动名词作表语，与主语部分可以转换，如Serving the people is our work,而⑥

句中是现在分词作表语，说明主语的性质、状态，现在分词具有形容词的各种特征，另外，动名词作表语还应与进行时态区别开来。

五、作状语

1）目的状语

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。

I come here only to say good-bye to you. 我来仅仅是向你告别。

2）作结果状语，表事先没有预料到的，要放在句子后面。

He searched the room only to find nothing.

3) 表原因

I'm glad to see you.

典型例题

The chair looks rather hard, but in fact it is very comfortable to ___.

A. sit

B. sit on

C. be seat

D. be sat on

答案：B. 如果不定式为不及物动词，其后应有必要的介词。当动词与介词连用时，常位于"

形容词+动词不定式"结构的末尾。

The water is too cold to drink.(不用被动)

六、作定语

⒈不定式作定语

不定式在句中作定语，置于被修饰的名词或代词之后。如：

①The next train to arrive is from Washington.

②Do you have anything to be taken ( to take)to your sister

③Do you have anything to say on the question

④Would you please giv e me some paper to write on

⑤My wish to visit France has come true at last.

不定式短语作定语和被修饰词之间表示以下关系：

(1)表示将来的动作（例①）。

(2)与被修饰词之间有动宾关系，如是不及物动词，则需加介词（例④）。

(3)与被修饰词之间有动宾关系，同时与句中其它词之间又有逻辑上的主谓关系时，尽管

有被动含义，却仍用主动语态（例③）；如只有动宾关系，而无逻辑上的主谓关系，则需用被动语态（例②）。

(4)不定式作定语时，一般可转换为定语从句，例①to arrive=that will arrive。七．省to 的动词不定式

介绍

1）情态动词 ( 除ought 外，ought to意思是"应该"，是情态动词，只有一种形式，后边接动词不定式，to不能省略。ought to没有人称和数的变化，后接动词原形可以表示现在、将来或过去将来，由时间状语或上下文决定。例如：

They ought to come tomorrow.他们明天应当来)：

2）使役动词 let, have, make：

3）感官动词 see, watch, look at, notice , observe, hear, listen to, smell, feel, find 等后作宾补，省略to。

注意：在被动语态中则to 不能省掉。

在使役动词中get除外(get sb. to do sth.)

I saw him dance.

=He was seen to dance.

The boss made them work the whole night.

=They were made to work the whole night.

4）表示个人意愿或倾向的would rather，had better，might(just) as well：rather than 置于句首时。

Rather than ride on a crowded bus, he always prefers to ride a bike.

5）Why… / why not…：

6） help 可带to，也可不带to, help sb (to) do sth：

7） but和except：but前是动词do时，后面出现的动词用不带to的动词不定式。

8）由and, or和than连接的两个不定式，第二个to 可以省去：

9）通常在discover, imagine, suppose, think, understand等词后，可以省去to be：He is supposed (to be) nice. 他应该是个好人。

10）but作介词，后接不定式结构时，前面谓语动词部分若含有do的形式时，but后的不定式要省去to，否则要带to。

He wants to do nothing but go out.

He wants to believe anything but to take the medicine.

11）当两个或多个不定式短语由连词and，but或or连接时，后一个或几个不定式符号to 常省略。但若表示对比、对照关系时，则不能省略。

He wants to move to France and marry the girl.

The purpose of new technologies is to make life easier, .

not to make it more difficult.

12）不定式做表语时，一般要带to，但若主语部分中含有do的各种形式时，符号to可省去。

We've missed the last we could do now is walk home.

典型例题

1) ---- I usually go there by train.

---- Why not ___ by boat for a change

A. to try going

B. trying to go

C. to try and go

D. try going

答案：D. why not 后面接不带to 的不定式，因此选D。

2） Paul doesn't have to be made ___. He always works hard.

A. learn

B. to learn

C. learned

D. learning

答案：B. make后接不带to 的动词不定式，当其用于被动时，to 不可省略。

13，在口语中,为避免重复,常用"to"代替不定式结构,有时甚至可以把to省略.如:

①-Did you go to visit the Great Wall

-No, I wanted to, but there wasn't enough time.

动词不定式的否定式...not to do...

Tell him not to shut the window…

She pretended not to see me when I passed by. 我走过的时候，她假装没看见。

典型例题

1）Tell him ___ the window.

A. to shut not

B. not to shut

C. to not shut

D. not shut

答案：B。 tell sb to do sth 的否定形式为tell sb not to do sth.

2) She pretended ___ me when I passed by.

A. not to see

B. not seeing

C. to not see

D. having not seen

答案：A。 pretend 后应接不定式。其否定形式为pretend not to do sth.。

3）Mrs. Smith warned her daughter ___ after drinking.

A. never to drive

B. to never driver

C. never driving

D. never drive

答案：A。warn sb to do sth. 的否定形式为warn sb not to do sth. 此处用的是否定词never.

4) The boy wanted to ride his bicycle in the street，but his mother told him ____.

A. not to

B. not to do

C. not do it

D. do not to

答案：A。not to 为not to do it 的省略形式。可以只用to这个词，而不必重复整个不定式词组。及物动词do后应有名词、代词等，否则不对，因此B，D不对。

5) The patient was warned ___ oily food after the operation.

A. to eat no

B. eating not

C. not to eat

D. not eating

答案：C。warn一词要求后用不定式，此处为不定式的被动，否定形式为be warned not to do。

八、不定式的特殊句型

不定式的特殊句型

so as to

1）表示目的；它的否定式是so as not to do。

Tom kept quiet about the accident so as not to lose his job.

汤姆对事故保持沉默是为了不丢掉他的工作。

Go in quietly so as not to wake the baby.

轻点进去，别惊醒了婴儿。

2) so kind as to ---劳驾

Would you be so kind as to tell me the time

劳驾，现在几点了。

2、 "Why not +动词原形"表达向某人提出建议

"为什么不……" "干吗不……"

例如：

Why not take a holiday

干吗不去度假

3、It's for sb.和 It's of sb.

1）for sb. 常用于表示事物的特征特点，表示客观形式的形容词，如easy, hard, difficult, interesting, impossible等：

It's very hard for him to study two languages. 对他来说学两门外语是很难的。

2）of sb的句型一般用表示人物的性格，品德，表示主观感情或态度的形容词，如good, kind, nice, clever, foolish, right。

It's very nice of you to help me. 你来帮助我，你真是太好了。

for 与of 的辨别方法：

用介词后面的代词作主语，用介词前边的形容词作表语，造个句子。如果道理上通顺用of，不通则用for。如：

You are nice. (通顺，所以应用of)。

He is hard. (人是困难的，不通，因此应用for。)

4、不定式的特殊句型too…to…

1）too…to太…以至于…

He is too excited to speak.

他太激动了，说不出话来。

---- Can I help you 需要我帮忙吗

---- Well, I'm afraid the box is too heavy for you to carry it, but thank you all the same. 不用了。这箱子太重，恐怕你搬不动。谢谢您。

2) 如在too前有否定词，则整个句子用否定词表达肯定， too 后那个词表达一种委婉含

义，意为"不太"。

It's never too late to mend. (谚语)

改过不嫌晚。

3) 当too 前面有only, all, but时，意思是：非常… 等于very。

I'm only too pleased to be able to help you. 我非常高兴能帮助你。

He was but too eager to get home. 他非常想回家。

[动词不定式的"to"与介词的"to"区别] to 有两种用法：

一为不定式+动词原形；

一为介词+名词/动名词, to 在下面的用法中是介词，即to+ 名词/动名词：

admit to承认，confess to承认，be accustomed to 习惯于，be used to 习惯于， stick to 坚持， turn to开始，着手于， devote oneself to 献身于，be devoted to 致力于，look forward to 盼望，pay attention to 注意，contribute to, object to 介词but,except,besides+to do(do)

在这种句型中，如介词前有动词do，后面应接不带to的不定式；如无do，则接to不定式，即带do不带to，带to不带do。如：

The enemy soldiers had no choice but to give in.

On Sunday afternoon I had nothing to do but watch TV.

九、动词不定式与动名词区别与联系

1 动名词与不定式的区别：

动名词表达的是：状态，性质，心境，抽象，经常性，已发生的

不定式表达的是：目的，结果，原因，具体，一次性，将发生的

2 接不定式或动名词，意义相同

3)在下列情况下，一般要用不定式：

①hate,like,love前有would(should)时，如：I'd like to have a cup of coffee.

②当谓语动词begin,continue,start等是进行式时，

如：The students are starting to work on the difficult maths problem.

③begin,continue,start与know,understand等状态动词连用时，如：I soon began to

understand what was happening.

⒋advise,allow,encourage,forbid,permit等动词后接动名词作宾语，或带不定式作宾语

补足语。如：

Our teachers don't permit our/us swimming in the lake.

Our teachers don't permit us to swim in the lake.

4）部分动词后接不定式或动名词时，意义差别较大，应根据句子语境选择使用。

①forget,remember,regret后接不定式，表示现在或未来的动作，接动名词表示动作已经

发生。如：

Don't forget to post the letter for me.

Have you forgotten meeting her in Beijing Airport

Remember to close the windows before you leave.

I remember writing him a letter a year ago.

We regret to tell you that all of you are not invited toattend the meeting.

They regretted ordering these books from abroad.

动名词与不定式语义不同的有11 组

1 stop to do/ stop doing

2 forget to do /forget doing

3 remember to do /remember doing

4 regret to do /regret doing

5 cease to do(长时间，甚至永远停止)/ cease doing（短时间）

6 try to do（尽力）、try doing（尝试）

7 go on to do go on doing

8 afraid to do不敢去做某事

afraid of doing 一向害怕做某事，表示习惯

9 interested to do对某事感兴趣，想了解、

interested doing 对某种想法感兴趣

10 mean to do打算、、mean doing 意味

11 begin/ start to do begin/ start doing

十，动词不定式的时态,语态

(1)时态

①一般式:动词不定式一般式表示的动作发生在谓语动词之后,有时表示同时发生.如:

I hope to become a university student this year.(to become发生在hope之后)

We often hear Dick play the piano in the next room.(play和hear同时发生)

②完成式:表示的动作发生在谓语动词所表示的动作之前.如:

I'm sorry to have kept you waiting.

We are too young to have seen the old society.

③进行式:表示的动作与谓语动词同时发生.如:

The teacher happened to be correcting our papers when I came in.

They seemed to be discussing something important.

(2)语态

如果动词不定式的逻辑主语是这个不定式所表示的动作的承受者,不定式一般要用被动语态形式.如:

It's a great honour to be invited to Mary's birthday party.(不定式作主语)

It was impossible for lost time to be made up.(不定式作主语)

I wish to be sent to work in the country.(不定式作宾语)

Can you tell me which is the car to be repaired (不定式作定语)

He went to the hospital to be examined.(不定式作状语)

在There be结构中,修饰主语的不定式可用被动,也可用主动.如:There are still many things to take care of (to be taken care of).但有时两种形式表达的意思不同,如:These is nothing to do now.( We have nothing to do now.) There is nothing to be done now.(We can do nothing now.)

不定式完成进行式与完成被动式的用法

一、不定式被动式的用法

不定式到底用主动形式还是被动形式，往往取决于句子的意思，即意思上为主动就用主动形式，意思上为被动就用被动形式：

Did it need to be done so soon 这事需要这么快就做吗

She can’t bear to be laughed at. 她受不了被人嘲笑。

There was business to be taken care of. 有生意要人管理。

It remains to be seen whether you are right. 你是否正确，以后见分晓。

There was a lot of rubbish to be got rid of. 有大量垃圾需要扔掉。

二、不定式完成被动式的用法

不定式的完成被动式表示发生在谓语动作之前的被动动作：

I’m pleased to have been given this opportunity. 给了我这次机会我很高兴。

It’s said to have been built in the Ming dynasty. 据说它是明朝修建的。

不定式完成式的三种用法

一、表示发生在谓语动作之前的动作

He seems to have caught a cold. 他似乎感冒了。

I hate to have quarreled with her. 我后悔和她吵架了。

I believe it to have been a mistake. 我相信这是一个错误。

You appear to have travelled quite a lot. 你似乎作过多次旅行。

I’m sorry to have given you so much trouble. 对不起给了你这么多麻烦。

It’s said to have bee n built in the Ming dynasty. 据说它是明朝修建的。

二、表示在某个给定的时间之前已完成的动作

I hope to have finished the work by now. 我希望现在以前已完成这项工作。

三、表示过去未曾实现的想法和愿望

I should like to have come earlier. 我本想早点来的。

We were to have been married last year. 我们本来打算去年结婚的。