动词不定式的用法
1. 不定式定义:由to＋动词原形构成。
不定式是一种非限定性动词。而非限定动词是指那些在句中不能单独充当谓语的动词，可分为不定式，动名词，现在分词和过去分词。
2.用途：
在句中不能作谓语。它具有动词的性质，本身可以带宾语和状语。
【动词不定式】
1.定义：动词 + 不定式
2.用途：
动词不定式在句中可以作句子任何成分。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]
不定式在句子中可做主语、宾语、表语、定语、状语和宾语补语。
1)不定式做主语一般表示具体的某次动作。
【例如】
To complete the 30 storied 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. It is 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 du ty, 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,choose,claim,consent,demand,decide,desire,determine,
expect,fail,hope,hesitate,hate,intend,learn,like,manage,mean,neglect,offer,plan,prepare
pretend,promise,refuse,resolve,seek,tend,threaten,want等。
【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, tell,ask,consider,discover,explain,findout,forget,guess,hear,imagine,inquire,learn,observe,
perceive,remember,think,understand,wonder等。
【例如】
I couldn't decide which book to choose. I can tell youswheresto get this book.They found it hard to decide
whether 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 painstaking efforts. Mother saved every cent she could spare to pay for my schooling.We must develop science and technology at
high speed so as to raise scientific and cultural level of our country. Insgroupsto get a high mark in Band 4, he did a lot of exercises 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 ready to, 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 neighbor girl 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, solve mathematical problems, compose music, walk through windows and commit murder in their sleep. He is reported to have won the 100 meter running race in 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, intention, need, opportunity, plan, promise, pressure, right, tendency, time, way等。
【例如】
His efforts to carry out the plan were successful.I have no intention to go to the cinema with you.
There is no need to bother him with such trifles.
There is a tendency to writer quite long sentences in 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) competing
C) 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 office and the last man to leave.I don't think he is the best one 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 help but...(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 library on 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.
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） would rather，had better：
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。
举例：
He wants to move to France and marry the girl.
He wants to do nothing but go out.
比较： He wants to do nothing but go out.
He wants to believe anything but to take the medicine.
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。