什么是动词不定式？

[动词不定式的简介]
动词不定式是一种非限定性动词，非限定动词是指那些在句中不能单独充当谓语的动词，分为不定式，动名词，现在分词和过去分词，由to＋动词原形构成，但在有些情况下to可以省略。在句中不能单独作谓语。它具有动词的性质，本身可以带宾语和状语。动词不定式在句中可以作除了谓语之外的任何成分，还可用在复合结构中，而且有完成式、进行式、完成进行式和否定形式。动词不定式的被动形式除了一般形式外还有其完成式和进行式。
[编辑本段][动词不定式的时态、语态]
动词不定式可以作以上各种成分，但它毕竟是动词，所以有动词的属性
动词不定式及其短语还可以有自己的宾语、状语，虽然动词不定式在语法上没有表面上的直接主语，但它表达的意义是动作，这一动作一定由使动者发出。这一使动者我们称之为 逻辑主语，其形式如下：
主动形式 被动形式
一般式 （not） to make （not） to be made
完成式 （not） to have made （not） to have been made
进行式 （not） to be making
完成进行式 （not） to have been making
(1)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 t ake 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.)
(2)时态
1) 现在时：一般现在时表示的动词，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.
I hope to see you again. = I hope that I'll see you again. 我希望再见到你。
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：
She is known to have been wreaking on the problem for many years.
[编辑本段][疑问词＋不定式结构]
疑问词who,what,which,when,where,whether,how后可接不定式构成不定式短语，在句中作主语、宾语、表 语等。如：
①When to leave for London has not been decided yet. （不定式在句子中做主语）
②Mr. Smith didn't know whether to leave or stay there. （不定式在句子中做宾语）
③I asked Professor Xu how to learn English well. （不定式在句子中做间接宾语）
④The question was where to get the medicine needed. （不定式在句子中表语）
以上例句中疑问词＋不定式部分，均可转换为相应的从句形式。如：①When we shall leave…③…how I
could learn…
经常在这种结构中使用的动词有：consider,decide,discover,explain,find out,forget,hear,know,lea rn,observe,understand,wonder等。
[编辑本段][动词不定式的语法功能]
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 compositionin a quarter of an hour.
④It＋be＋形容词＋of sb＋to do
It is stupid of you to write down everything the teachersays.
⑤It seems(appears)＋形容词＋to do
It seemed impossible to save money.
在句型③中，常用表示客观情况的形容词，如：difficult,easy,hard,important,impossible,necessary 等；在句型④中，常用careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise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'skind of you to help me with my English.=You are kind to helpme with my English.
(3)举例
1） It's easy (for me) to do that.我做这事太容易了
easy, difficult, hard, important, possible, impossible, comfortable, necessary, better;
the first, the next, the last, the best, too much, too little, not enough
It's so nice to hear your voice.
听到你的声音真高兴。
It's necessary for you to lock the car when you do not use it.
当你不用车的时候，锁车是有必要的。
2) It's very kind of him to help us. 他帮助我们，他真好。
Kind, nice, stupid, rude, clever, foolish, thoughtful, thoughtless, brave, considerate(考虑周到的), silly, selfish(自私的)
例句:
It was silly of us to believe him. 我们真愚蠢，竟然相信了他。
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) 不定式作为句子成分时，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)To see is to believe. 百闻不如一见。
(错)It is to believe to see.
二、作宾语
1) 动词+ 不定式
afford. aim. appear. agree. arrange . ask . be . decide. bother . care . choose . come. dare. demand. desire. determine . expect. elect . endeavor .hope. fail . happen . help . hesitate .learn . long . mean. manage . offer . ought. plan . prepare. pretend . promise. refuse. seem. tend. wait . wish. undertake.
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+不定式 ；动词+宾语+不定式
ask, beg, choose, expect , hate, help intend like, love, need prefer, prepare, promise, want, wish…
I like to keep everything tidy. 我喜欢每件东西都保持整洁。
I like you to keep everything tidy. 我喜欢你使每件东西都保持整洁。
I want to speak to Tom. 我想和汤姆谈话。
I want you to speak to Tom. 我想让你和汤姆谈话。
3） 动词+疑问词+ to
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成分时，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。
4)以下动词后，只能跟不定式作宾语。
如：agree,ask,aim,arrange,choose,decide,demand,expect,fail ,help,hope,lean,long,manage,offer,plan,prepare,
pretend,promise,refuse,wish 等，这些词大部分可接that引导的从句。如：
I decided to ask for my money back.
I decided that I would ask for my money back.
When our visit to the farm was over,we expected to startback on foot.
When our visit to the farm was over, we expected that wewould start back on foot.
5)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 foreignlanguage well.
He feels it his duty to help the poor.
三、作补语
1) 动词+宾语+不定式(to do)
advise allow appoint believe cause challenge command compel consider declare drive enable encourage find forbid force guess hire imagine impel induce inform instruct invite judge know like order permit persuade remind report request require select send state suppose tell think train trust understand urge warn
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。
2) to + be 的不定式结构，作补语的动词。
Acknowledge, 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。
典型例题
Charles Babbage is generally considered ___ the first computer.
A. to invent B. inventing C. to have invented D. having invented
答案：A. 由consider to dosth. 排除B、D。. 此句只说明发明这一个事实，不定式后用原形即可。而C为现在完成时，发明为点动词一般不用完成时，且此处也不强调对现在的影响，因此不选C。
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.
人们认为这本书没什么意思。
4) there be+不定式
believe, expect, intend, like, love, mean, prefer, want, wish, undrstand
We didn't expect there to be so many people there.我们没料到会有那么多人在哪里。
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 ofthe 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 thepeople 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。
What have I said to make you angry.
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。
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.
②Have you anything to be taken to your sister?
③Do you have anything to say on the question?
④Would you please give 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。
[编辑本段][省to 的动词不定式]
1） 情态动词 ( 除ought 外，ought to)：
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。
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）当两个或多个不定时短语由连词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 bus.All 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。
[编辑本段][动词不定式的否定式]
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。
[编辑本段][不定式的特殊句型]
1、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 在下面的用法中是第二种，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
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.
[编辑本段][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：Thestudents are starting to work on the di fficult 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 fo 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 cease doing
6 try to do try doing
7 go on to do go on doing
8 afraid to do afraid doing
9 interested to do interested doing
10 mean to do mean doing
11 begin/ start to do begin/ start doing
1 forget doing/to do
forget to do 忘记要去做某事。 (未做)
forget doing 忘记做过某事。 (已做)
The light in the office is stil on. He forgot to turn it off.

[动词不定式的简介]
动词不定式是一种非限定性动词，非限定动词是指那些在句中不能单独充当谓语的动词，分为不定式，动名词，现在分词和过去分词，由to＋动词原形构成，但在有些情况下to可以省略。在句中不能单独作谓语。它具有动词的性质，本身可以带宾语和状语。动词不定式在句中可以作除了谓语之外的任何成分，还可用在复合结构中，而且有完成式、进行式、完成进行式和否定形式。动词不定式的被动形式除了一般形式外还有其完成式和进行式。
[编辑本段][动词不定式的时态、语态]
动词不定式可以作以上各种成分，但它毕竟是动词，所以有动词的属性
动词不定式及其短语还可以有自己的宾语、状语，虽然动词不定式在语法上没有表面上的直接主语，但它表达的意义是动作，这一动作一定由使动者发出。这一使动者我们称之为 逻辑主语，其形式如下：
主动形式 被动形式
一般式 （not） to make （not） to be made
完成式 （not） to have made （not） to have been made
进行式 （not） to be making
完成进行式 （not） to have been making
(1)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 t ake 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.)
(2)时态
1) 现在时：一般现在时表示的动词，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.
I hope to see you again. = I hope that I'll see you again. 我希望再见到你。
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：
She is known to have been wreaking on the problem for many years.
[编辑本段][疑问词＋不定式结构]
疑问词who,what,which,when,where,whether,how后可接不定式构成不定式短语，在句中作主语、宾语、表 语等。如：
①When to leave for London has not been decided yet. （不定式在句子中做主语）
②Mr. Smith didn't know whether to leave or stay there. （不定式在句子中做宾语）
③I asked Professor Xu how to learn English well. （不定式在句子中做间接宾语）
④The question was where to get the medicine needed. （不定式在句子中表语）
以上例句中疑问词＋不定式部分，均可转换为相应的从句形式。如：①When we shall leave…③…how I
could learn…
经常在这种结构中使用的动词有：consider,decide,discover,explain,find out,forget,hear,know,lea rn,observe,understand,wonder等。
[编辑本段][动词不定式的语法功能]
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 compositionin a quarter of an hour.
④It＋be＋形容词＋of sb＋to do
It is stupid of you to write down everything the teachersays.
⑤It seems(appears)＋形容词＋to do
It seemed impossible to save money.
在句型③中，常用表示客观情况的形容词，如：difficult,easy,hard,important,impossible,necessary 等；在句型④中，常用careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise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'skind of you to help me with my English.=You are kind to helpme with my English

动词不定式是一种非限定性动词，非限定动词是指那些在句中不能单独充当谓语的动词，分为不定式，动名词，现在分词和过去分词，由to＋动词原形构成，但在有些情况下to可以省略。在句中不能单独作谓语。它具有动词的性质，本身可以带宾语和状语。动词不定式在句中可以作除了谓语之外的任何成分，还可用在复合结构中，而且有完成式、进行式、完成进行式和否定形式。动词不定式的被动形式除了一般形式外还有其完成式和进行式。
一、不定式的基本形式: to＋动词原形,有时可以省略to.

二、 动词不定式的特点: （1）没有人称和数的变化,在句子中不能作谓语.

（2）动词不定式仍保留动词的特点,可以有自己的宾语和状语.动词不定式同它的宾语或状语可构成动词不定式短语.如: to read a book; to sing at the party.

（3）动词不定式具有名词、形容词和副词的特征,因此,在句中可以作主语、表语、宾语、宾语补足语、定语和状语.

三、动词不定式作宾语.即不定式直接跟在谓语动词后,是谓语动词涉及的直接对象.如果没有这个不定式,这个句子的意思就让人难以理解. 能直接带不定式作宾语的及物动词主要有: want, like , love , need , try , ask , learn , begin , start , forget , remember, hope , wish , agree, choose , fail , refuse , decide , afford , offer , make sure , take turns , would like , plan , hate , try one’s best 等.

四、动词不定式作宾语补足语. 能用动词不定式作宾语补足语的动词有: ask , tell , get , order , would like , want , teach , show , allow , encourage , warn , wish , invite ,help等.

五、动词不定式作状语: 即不定式直接跟在谓语动词后,仅对谓语动词起一个补充说明的作用.如果没有它,句子仍然意思完整,它不象作宾语那样,与谓语动词有着密切的关系.（1）表示目的: The doctor came to operate on her. He has gone to town to do some shopping. I sat down to have a rest. He stopped to have a look. He rushed into the room to save the girl. The moved away the stone to let the traffic go. He got up to catch the train.

（2）表示结果: The girl cried only to make her mother angry.

（3）表示程度: She is too tired to walk any farther. She is strong enough to carry the heavy box.

（4）表示原因: I was surprised to read the news.

能带不定式作状语的形容词有: glad , happy , pleased , angry , clever , careful , surprised , lucky ,ready ,sorry, amazed , afraid ,sad , unhappy , sure , free ,kind, nice , worried , easy , hard

六、不定式作定语: 动词不定式作定语,一般要放在被修饰词的后面,不定式与所修饰的词构成动宾关系. We have lots of work to do. Would you like something to drink? I want to get something to read during my holiday. That’s a difficult question to answer.

【注意】如果动词不定式是不及物动词,后面就应有必要的介词. 如: He is looking for a room to live in. Give me a piece of paper to write on. He has nothing to worry about. There is not enough space to stand in on the earth.. She is a nice person to work with. a place to go to.

七、动词不定式作主语: 如 To learn a foreign language is not easy.

在现代英语中,常用it来作形式主语,而把真正的动词不定式主语放在后面.即句型:

“It is＋形容词＋for （ of） sb. to do sth.”中，当形容词是kind ，nice ， good ， clever ， careful ， careless , right , wrong , foolish 等表示人的性格特征时, 用of ; 如果形容词为difficult , easy , hard, important ,interesting, possible ,necessary 等表示事物的特征时, 用for. It is necessary / important / easy / hard/ possible for us to learn English well. It is very kind /nice / good of you to help me with my English.

※ 在句型: 主语＋find / think / feel / make +it +形容词+ to do sth.中,it为形式宾语.

I found it very important to learn English well. I think it easy to learn English well.

八、作表语: My job is to teach English. His wish is to become a scientist.

九、动词不定式和疑问词连用.动词不定式可以和疑问词what, which , how , when , where ,who 等连用,构成不定式短语,在句子中作主语、宾语、表语等成分.这时往往可以扩写成宾语从句; The question is how to use the computer.

I don’t know where to go for my holiday =I don’t know where I can go for my holiday.

He can’t decide which book to choose.= He can’t decide which book he can choose.

I don’t know what I should do next=I don’t know what to do next.

十、动词不定式的否定形式: not to＋动词原形

Tell him not to be late. I will try not to read in bed.

十一、动词不定式省略to的场合:（1）作动词let, make , have, feel ,hear, see , watch , notice 等的宾语补足语时,动词不定式不带to. Let him do the work. He made me work day and night. I saw him fall off the bike.

（2）作动词help的宾语补足语时,动词不定式可带to,也可不带to.

He didn’t help me（to）mend the bike. You have helped ( to ) protect our environment.

（3）在助动词和一些情态动词如will , would , shall , should , can , could , may , might , must , do , does , did , didn’t , don’t , doesn’t 等的后面,用动词原形,即动词不定式不带to.

Will you help me? He doesn’t live here. It might rain . You must finish your homework on time.

（4）在why not…? , had better , would rather 等的后面也跟不带to的动词不定式.（原形）

Why not buy a dictionary? You had better （not）stay at home. I would rather go early.

（5）在第二个不定式前一般不带to. I would like to lie down and go to sleep.

Do you want to eat now or wait till later?

※ 在下列答语中, to不能省略: －Will you join me in a walk?－I will be glad to.

－Will you go swimming with me this afternoon?－I would love to.

－Used he work in the factory?－Yes , he used to .

Exercises:

1. We must find a person （做这项工作）

2. In my family, my mother is always the first one （起床）

3. Do you have （什么问题要问）?

4. There are （许多重要事情要谈）

5. This book is （不容易理解）

6.He was too excited （说不出话来）

7. Do you think him easy （容易相处）?

8. You must get him （今晚顺便到这儿来）

9. It was not good （早晨起床晚）

10. It was a mistake （没有帮他学英语）

11. Her wish is （成为一名大学生）

12.What worries me is （在会上演说些什么）

13. It is our duty （保护家园）

14. I opened the door （让新鲜空气进来）

1)不定式做主语一般表示具体的某次动作。

【例如】To complete the 30storied building in one year was

quite a difficult task.

To do that implies taking responsibility.

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。

【例如】It is important for modern young people to master at least two foreign languages.

It做形式主语，不定式放在谓语动词之后常用

于下列结构中：

a) It is＋形容词(easy, important, difficult, foolish, inconvenient, unnecessary, right, wrong...)＋( for/of sb.)＋不定式

【例如】It is essential to reserve a table in advance of Christmas Eve. hard to put my hopessintoswords.

It is not easy to catch fish with your hands only.

It is important for us young people to learn English and master it.

b) It is＋名词(a pleasure, a pity, a pleasant thing, one’s duty, an honor, a shame, a crime, no easy job...)＋不定式

It is a sheer waste of time to read that kind of trash.

It is a pity to have to go without her.

It is a glorious death to die for the people.

c) It takes (sb.) some time (hours, months, days, a lot of time, patience...)＋不定式

It takes me three hours to learn English each day.

It took them half the night to get home in the snow.

2)不定式作表语不定式作表语常表示将来的动作，主语常常是表示意向、打算、计划的词，如wish, idea, task, purpose, duty, job等。

【例如】The most important thing for one’s health is to have plenty of exercise.

My chief purpose has been to point out the difficulties of the matter.

The purpose of the organization is to greet all new comers to the city and to provide them with any necessary

information. What I wanted was to get the work done as quickly as possible.

3)不定式作宾语不定式常在下列动词后面作宾语：

afford,agree,apply,arrange,ask,attempt,beg,begin,care,

【例如】I like to go out for walks in the warm sunshine in spring.

My mother hates to move from place to place, for she feels tired.I decide to work hard and get doctor’s degree.

The room is designed to be my study,but now it has to be used as a bedroom for the children.

She failed to finish the assignment in time, and she was worried about it.

There is a man at the reception desk who seems very angry and I think he means( )trouble. (CET-4 1997, 1)

A) making B) to make C) to have made D)shavingsmade

mean后面一般加不定式，所以A和D可以排除。根据句意，他看起来非常生气，他想找麻烦，不定式的动作还没有实施， 应用一般式，因此答案为B。不定式作宾语还常用在下面结构中；主语＋动词＋it＋形容词＋不定式。

【例如】 We found it impossible to get everything ready in time.I think it important to learn English well in college.使用这种句型的常见动词有：believe, consider, declare, feel,find, guess, imagine, prove, realize, suppose, think,等。

4)“wh�word＋不定式”结构不定式前加一个疑问代词(what,which, who, whom, whose)或疑问副词(where, when, how, why)，以及连词whether构成特殊的不定式短语，其作用相当于一个从句，这样的不定式短语常在某些动词后面作宾语。常见的可以接这种不定式短语的动词有：know, see, decide，等

【例如】 I couldn’t decide which book to choose. I can tell yous wheresto get this book.They found it hard to decidewhether to go swimming next Sunday or to visit Aunt Sally in New Year.“wh�word+不定式”结构除了作宾语外，还可以在句中作主语或者表语。

【例如】When to start the program remains undecided.The question is how to put the plansintospractice.

5)不定式作状语

a)不定式作状语表示目的。或用于so as和in order之后，来强调这种目的。

【例如】 To learn a foreign language well, you must make painstakingefforts. Mother saved every cent she could spare to pay for my schooling.We must develop science and technology at high speedso as to raise scientific and cultural level of our country.Insgroups to get a high mark in Band 4, he did a lot ofexercises both in grammar and reading comprehension.

b)不定式表示结果，特别是在so...as to, such...as to,only to...以及too...to等结构中的不定式表示结果。

【例如】 I rushed to the station as fast as I could, only to find the train already gone.She left her hometown with her beloved man, never to return.No one is too old to learn.Would you be so kind as to carry the luggage for me?

c)不定式常用来修饰形容词，构成下列词组：be able to,be afraid to, be apt to, be bound to, be certain to, be easy to, be eager to, be fit to, be likely to, be readyto, be sure to, be unable to, be unwilling to, be willing to等。

【例如】 Chinese team is bound to win the World Cup.It is likely to rain today, for it is very cloudy.I am willing to help you with your homework, for we are friends.

6)不定式作宾语补语不定式常跟在下列动词之后作宾语补语：ask, advise, allow, beg, cause, compel, command, enable, encourage, expect, feel, force, find, hear, have,inform, invite,let, make, mean, notice, order, permit, persuade,remind, require, request, teach, tell, urge, watch,warn, watch等。

【例如】Because of the complexity of the modern equipments,most offices require secretaries to have specified training.He asked you to call him at ten o’clock. The note reminds me to be careful whatever I do.I’d never allow my children to behave like that.当不定式在let, make, have, hear, look at, listen to,feel, observe, watch, notice, perceive(感觉到)等动词后面作宾语补语时，不定式不带to.

【例如】Whenever something is wrong with you,please do let me know.I will have the students write a passage about Internet.I saw my mother shed tears at the news that the neighborgirl got seriously hurt in a car accident.It seemed so long before he heard the stone hit the water.

7)不定式作主补带有宾语及宾语补足语结构的动词变为被动语态时，

原来的宾语变为主语，宾补则变为主补。加主补的动词主要有：assume,believe, know, report, say, suppose等。

【例如】Mr. Brown is said to have left for Italy last week.(It is said that Mr. Brown left for Italy last week.)Persons have been said to climb on roofs, solvemathematical problems, compose music, walk throughwindows and commit murder in their sleep He is reported to have won the 100�meter running racein the Olympic games.

8)不定式作定语

a)不定式作定语通常要放在其所修饰的名词或代词之后。

不定式常作下列的名词定语：attempt, ability, anything,chance, desire, determination, decision, effort, failure,ntention, need, opportunity, plan, promise, pressure,right, tendency,time, way等。

【例如】His efforts to carry out the plan were successful.I haveno intention to go to the cinema with you.There is no need to bother him with such triflesThere is a tendency to writer quite long sentencesin commercial correspondence.The pressure( )causes Americans to be energetic,but it also put them under a constant emotional strain.(CET-4 1997,6) A) to compete B) competingC) to be competed D)shavingscompeted

pressure后面应接后置定语，表示竞争的压力。单个分词作定语一般置于名词前，故B和D可以排除。C为不定式的被动式，而竞争和压力之间没有被动关系，因此正确答案为A。特别注意的是在不定式与其修饰的名词有动宾关系时，要根据句子的需要在不定式后加适当的介词，这个介词的选用取决于被修饰的名词或不定式本身的要求。

【例如】She is a very nice person to work with.This is an important issue to talk about.

b)由only, last, next,序数词或形容词最高级修饰的名词常用不定式作定语。

【例如】

Mr. Zhang is always the first man to arrive at the officeand the last man to leave.I don’t think he is the bestone to do the work.

9)不带to的不定式在下列词组后面的不定式不带to：would rather ...than(宁愿……也不), had better...(最好)，can’t helpbut...(不得不), had rather...(宁愿)，cannot but...(不得不，必然)，may/might as well...(不妨)， let alone(更不用说)。

【例如】 You’d better return the books to the libraryon time. Otherwise, you will be fined. I can’t help but wish that nothing would go wrong.They had never seen such delicious food, let alone eat it.

动词不定式是一种非限定性动词，非限定动词是指那些在句中不能单独充当谓语的动词，分为不定式，动名词，现在分词和过去分词，由to＋动词原形构成，但在有些情况下to可以省略。在句中不能单独作谓语。它具有动词的性质，本身可以带宾语和状语。动词不定式在句中可以作除了谓语之外的任何成分，还可用在复合结构中，而且有完成式、进行式、完成进行式和否定形式。动词不定式的被动形式除了一般形式外还有其完成式和进行式。