Ⅰ. 动词不定式形式
1.动词不定式的一般式
主动形式 （not）to do
被动形式 (not）to be done
不定式的一般式，表示即将要做的事或为了某目的要做的事，
She wanted to be a doctor when she grew up.
He asked to be sent to work in the countryside．
It is possible for our hopes to be realized．
2.动词不定式进行式
（not）to be doing
不定式的进行式，表示正在做的事。
Some students pretended to be reading English when the teacher came in.
I am very glad to be working with you．
3.动词不定式完成式
主动形式（not）to have done
被动形式（not）to have been done
不定式的完成式to have done ，表示事情已经先完成了,
I’m sorry to have kept you waiting.
He is said to have left the stage already as he has become an official.
Tom was pleased to have been invited to the party.
4.动词不定式完成进行式
（not）to have been doing
不定式完成进行式to have been doing 表示事情已经做了，而且还在进行中，
He seems to have been waiting here for a day.
He was said to have been living in London for twenty years.据说他在伦敦一直住了20年。
I'm sorry to have been interrupting you.
Ⅱ.不定式的用法
1 作主语
To serve the people is my great happiness.
不定式作主语时多用代词it代替不定式作形式主语，常见句型如下：
a．It is + adj (easy, important, difficult…) + 不定式
b. It is + n (a pity, a pleasure, one’s duty, a shame) + 不定式
c. It takes/needs/requires + some time (hours, months, days, patience…) + 不定式
It’s important for us to learn English well.
It’s my duty to teach you how to be a useful person.
It requires patience to be a good teacher.
注意：
当主语和表语都是不定式时，不能用形式主语代替动词不定式。
To respect others is to be respected.尊重别人就是尊重自己。
To become a slave is to give up one's freedom.做奴隶就等于放弃自由。
2 作宾语
A.常见接不定式作宾语的动词：
agree, afford, aim, ask, attempt尝试, choose, continue继续 decide决定, desire要求,determine, expect, fail,hope, learn, intend, manage, offer, plan, promise, pretend假装,seem,tend, refuse,want, wish .
(接to do作宾语的动词妙记--mecarfipsd霉咖啡不是的manage, expect, choose, afford/ agree/ attempt, refuse, fail,intend, plan/pretend/promise,seem,decide/desire/determine)
I offered to help her, but she refused.
He pretended not to hear me.
B. it作形式宾语，常放在动词feel, think, find, believe, consider, make等后。例如：
I find it interesting to work with him.
We feel it our duty to help others.
Science and technology has made it possible for man to fly in space.
C.疑问词who，which，when，where，how，what +不定式动词常在动词teach、decide、wonder、show、learn、forget、ask、find out、advise、know等后作宾语
He didn’t know what to say.
Can you teach me how to use the computer?
注1：也可充当主语、表语等．
How to solve the problem is very important．
My question is when to start.
注2：why或 why not后面紧跟的动词不定式不带 to.
例如: Why not have a rest?
D不定式表示虚拟 在表示“希望、打算”等动词（如hope, expect, intend, mean, want等）的过去式后，可接动词不定式的完成式来表示没有实现的动作即虚拟。
I hoped to have met him at the railway station, but he didn't turn up.我本希望在火车站接到他，但他未露面。
We would love to have gone to the match, but the tickets were all sold out.
我们原想去看这场比赛的，但票已售完了。
I intended to have called on you, but was prevented from doing so.我原想来拜访你的，但没来成。
I expected to have met him here last night.我以为昨天晚上能在这里见到他。（但没做到）
We meant to have stayed there a week.我们原打算在那儿呆一个星期的。
I wanted to have dropped her a line, but forgot to do so.我原想写一封信给她，但忘记了。
The plane was to have taken off at 9, but something went wrong.飞机原计划九点起飞，但出现了一些故障。
提示：
表示“原打算、原以为”还可以用这些动词hope, expect, intend, mean, want的过去完成时来表达。
I had intended to call on you.我原想来拜访你的。
I had expected to meet him here last night.我原以为昨天晚上能在这里见到他的。
We had meant to stay there a week.我们原打算在那儿呆一个星期的。
E．作介词but，except，besides的宾语
如果这些介词前有行为动词 do的各种形式，那么他们后不带 to，否则要带 to．
She could do nothing but cry.，
What do you like to do besides swim?
There is nothing we can do but wait patiently. 我们只能耐心等待。
注：在cannot but, cannot choose but, cannot help but，why, why not、had better, had best, would rather...than, would sooner...than, rather than, 等结构后直接跟动词原形或not +动词原形。
Why make so much noise 为什么发出这么大的噪音？
Why not join us 为什么不加入我们？
You'd better listen to your teacher's opinion. 你最好听一听老师的意见。
We had best call for the doctor at once.我们最好马上就请医生来。
She can't do anything but ask silly questions.她一直在问一些愚蠢的问题。
Rather than ride on a crowded bus, he always prefers to ride a bicycle.他宁愿骑自行车，也不愿挤公共汽车。
He cannot but move to another street, because his building has to be pulled down soon.
他不得不搬到另一条街上去，因为他住的大楼很快就要被推倒。
We cannot help but admire his courage. 我们情不自禁地钦佩他的勇气。
在一些固定搭配中用不带to的不定式。
He let go the rope.他松开了绳子。
I hear say there will be an earthquake soon.我听说不久就要有一次地震。
She made believe she was innocent.她假装清白。
在口语中，动词原形come和go后可接不带to的不定式。
Go tell her.去告诉她吧。
Come have a glass.来喝一杯。
F．作形容词的宾语
有两种句型，一个是句子的主语是不定式的逻辑主语，另一个是句子的主语是不定式的逻辑宾语。
在这种结构中，不定式是主动的
①句子的主语是不定式的逻辑主语。
形容词有:
able,afraid,angry,anxious,careful,clever,content,cruel,determined,disappointed,eager, foolish,fortunate,frightened,happy,impatient,glad, lucky, naughty, prepared, proud, ready, slow, shocked, sorry, surprised, willing等。
I am sorry to say that he is going from bad to worse. 很遗憾，他的情况每况愈下
She was not content to live a quiet life in a small town.
她不满足在一个小镇里过默默无闻的生活。
John was happy to be given the job.约翰得到这份工作很高兴。
②句子的主语是不定式的逻辑宾语。形容词有easy, hard, cheap, expensive, dangerous, difficult, funny, fit, impossible, interesting, nice, pleasant, simple, strange, useful等。
This problem is easy to solve.这个问题很容易解决。
The water is not fit to drink.这水不适于饮用。
She is hard to get along with.她这个人很难相处。
注意：如果不定式是不及物动词，则必须加上结构或含义所需的介词。
The river is dangerous to swim in.在这条河里游泳很危险。
A spring mattress is comfortable to sleep on.席梦思床垫睡上去很舒服。
3 作表语: 位于be动词之后。
be +不定式”结构可以表示将来发生的动作，常有以下几种情况：
1)．表示命令和指示
The room is to be locked.这房间要上锁。
You are not to stand here.你不可以站在这里。
2)．表示计划或安排
We are to begin the work next month.我们安排下一个月开始这项工作。
What's to be done next下一步该怎么办？
3)说明主语的具体内容或表示目的。“
My job is to help the patient．
Our most important task now is to make a plan.
His wish is to become an astronaut. 他的愿望是成为一名宇航员。
What he hoped was to be admitted into the university.他希望能被大学录取。
To live is to do something worthwhile.活着就是要做一些有价值的事情。
注1：
有些作表语的不定式，在结构上是主动的，但在意义上却是被动的。
She is to blame.她应该受到责备。
The house is to let.此房出租。
The result is not long to see.结果不久就会看到。
注2：作表语的不定式都带to，但当主语部分有实义动词do时，to可以省略。
The only thing we can do now is wait and see.
4 不定式作定语
放在其修饰的名或代词之后，和被修饰的名词或代词之间是主谓关系、动宾关系、同位关系和修饰关系。
1）主谓关系
He is always the first person to come and the last one to leave.
The next train to arrive was from New York.
The future to greet us will be bright.我们的未来会十分美好的。
2）动宾关系
On Sundays, he always has a lot of letters to write.星期天，他总是有许多信要写
The teacher left us a lot of problems to solve.老师给我们留了许多道题要解答。
He can find no one to make friends with.他找不到可交朋友的人。
注意：由于动词不定式与其修饰的词之间往往有动宾关系，因此，如果该不定式是不及物动词，其后应
有必要的介词。
He is looking for a room to live in．
There is nothing to worry about．
Please give me a knife to cut with．
She has a child to take care of.
她有一个孩子要照看。
He has no friend to depend on.
I've got a lot of things to see to this morning. 今天上午我有许多事情要处理。
但是,不定式所修饰的名词是 time，place或 way，介词可以省去。
He had no money and no place to live.
3）同位关系
He broke his promise to write to his parents regularly.他没有遵守诺言定期给他父母亲写信。
We students should have the courage to face any difficulty.I have no wish to quarrel with you.我不想和你吵架。
4）修饰关系
Now it is time to begin our class.现在是上课的时间了。I need somewhere to take a nap.我需要个地方打个盹。
Is that the way to open the can那就是打开罐头的方法吗？
注意1：下列名词后常接不定式作定语：the first、the last、the only，chance、opportunity、promise、wish、right、courage、need、time、way、等。
He is always the first to come and the last to leave.
注意2：不定式在句中用主动式还是被动式,
不定式修饰的名词或代词和不定式逻辑上构成主谓关系时，不定式往往用主动形式.
Have you got a key to unlock the door?(A key unlocks the door．)
b. 不定式和它前面被修饰的名词或代词构成逻辑上的动宾关系，又和该句主语构成逻辑上的主谓关系时，不定式常用主动形式，否则用被动。
Do you have anything to say on this question针对这个问题你有什么要说的吗？
He is a pleasant person to work with.他是一个与其合作起来令人感到愉快的人。
I have got a report to write．我有一个报告要写。I have got a report to be written．（别人写）
I know what to do．（我自己做）I know what is to be done.我知道能做什么。（表示别人做）
c．There be结构中，当说话人考虑必须有人去完成某件事时。
There is nothing to worry about.没什么可担心的。
There is nothing to fear.没有什么可害怕的。
There is a lot of work to do.有许多事情要做。（表示某人必须做这工作）
There is a lot of work to be done.有许多事情要做。（强调有许多事情必须做）
5 作宾语补足语
“主语+谓语+宾语+宾语补足语”, 不定式作宾语补足语，宾语是动词不定式的逻辑主语。
1)．在感官动词后作宾语补足语，不定式都不带to。这类动词：一感二听三看。
feel, listen to,hear, look at, see,watch, notice,find, observe, 等。
I felt something crawl up my leg.我感到有什么东西爬到我腿上了。
I heard them sing yesterday.昨天我听见他们唱歌了。
Did you see him go out你看见他出去了吗？
注意：转为被动语态时，原不带to的不定式要变成带to的不定式。notice和watch没有
被动语态。
We saw the car stop.
The car was seen to stop.
He is often listened to to sing the song．
2)．在使役动词后作宾语补足语，不定式不带to。
这类动词有三让：make, let, have等。转为被动语态时，其后通常都用带to的不定式（have没有被动语
态）。此时不定式叫主语补足语
What would you have me do你要我做什么？
She made him give up smoking.她让他戒了烟。
Let him do whatever he wishes to do.他想干什么就让他干吧。
Though he had often made his little sister cry, today he was made to cry by his little sister.
The students were usually made to recite the text.
注 在help后，不定式可以带 to也可以不带 to。
Would you please help me (to) repair my bike?
3)．在表示心理状态的动词后作宾语补足语。有：consider, think, believe, discover, find, imagine, judge, suppose, prove等。这类动词后的不定式通常是“to be+形容词或名词”结构，think, consider, find后的to be常可省略。
We consider him (to be) a good teacher.我们认为他是一个好老师。
He proved that theory (to be) very important. 他证明那个理论是很重要的。
I thought her (to be) nice and honest the first time I met her.
4)．在表示情感状态的动词后作宾语补足语。有：beg,love, like, prefer, hate, want, wish, expect等。
I'd prefer you to leave him alone.我希望你不要打扰他。
I don't want there to be any trouble.我不想有任何麻烦。
5)．动词advise, allow, ask, beg, command, enable, expect,tell, invite, force, oblige, get, help, encourage, persuade, permit, remind, request,teach, order, warn, cause等后面，多接不定式短语作宾语补足语。
He asked me to do the work with him.
You should get more people to help you.
The teacher expected everyone to study
hard.
We don't allow such things to happen
again.
Most of the parents agree to forbid their
children to smoke.
She requested him to go with her.
She asked me to answer the phone in her
absence.
Please remind me to leave her this note.
注意：hope, demand, suggest等动词后面不能接不定式作宾语补足语。
【误】I hope you to give me a hand.【正】I hope you can give me a hand.我希望你能帮我一把。
【正】I wish you to give me a hand.我希望你能帮我一把。
【误】He demanded me to be present at the meeting.
【正】He demanded that we should be present at the meeting.他要求我们出席会议。
【正】He required us to be present at the meeting.他要求我们出席会议。
【误】Mr Li suggested her not to go there alone.
【正】Mr Li suggested that she should not go there alone.
6)．动词不定式也可作一些短语动词语动词call on号召 arrange for 安排long for盼望 wait for等待 depend on 依靠 rely on 指望，等的宾语补足语。
I'm waiting for James to arrive.
He's arranged for a car to pick them up at the station.
The UN has called on both sides to observe the ceasefire.联合国号召交战双方遵守停火协定。
6 作状语，
1）表示原因（表语形容词后面加不定式作状语）
We were very excited to hear the news． I was a fool not to listen to you at that time.
She wept to find him in such a difficult situation.看到他处于这么困难的情形，她哭了。
2) 表示目的
I'm saving up to buy a computer. To save the child, he laid down his life.为了救那个孩子，他献出了生命。
注意：也可以用in order (not) to do,和so as (not) to do结构（so as to do 不可以置于句首）。
He shouted and waved in order to be noticed. We ran all the way so as not to be late．
In order to pass the exam, he worked very hard． I'll write down his telephone number so as not to forget it.
3) 表示结果
What have I said to make you so angry我说了什么话使你气成这样？
After the meeting, they parted, never to see each other again.
不定式表示结果常见于下列句型。
1）so ... as to do
Would you be so kind as to lend me your bicycle把你的自行车借给我好吗？
2）such ... as to do
We are not such fools as to believe him.我们还没蠢到竟会相信他。
3）enough to do
He didn't run fast enough to catch the train. 他跑得不够快,没赶上火车。
4）only to do
He hurried to the station ,only to be told the train had gone.
He lifted a rock only to drop it on his own feet.他搬起石头砸自己的脚。
5）too ... to do， not/never too…to并非……太而不能， too..not to...非常(很,太,那么)……不会不(必定能,所以能)……，
His eyesight is too poor to read such small letters.
One is never to old to learn
He is too careful not to have noticed that. She is too sad not to help crying.
注意：
(but /only )too...to do是非常...去做... 结构中的形容词如果是easy,eager, glad,pleased, happy, ready等，动词不定式不表示结果，也没有否定的意思。
The boy was too eager to get a geography book.那个男孩非常急切地想要得到一本地理书。
He is too anxious to know the examination results.他很急切地想知道考试结果。
They're but too glad to go to the concert.
4）表示条件
To look at him, you would like him．
A man would be blind not to see that.一个人如果看不到这点，那他就是瞎子。
How can you catch the train to start so late这么晚才动身，你怎么能赶上火车？
7. 不定式的复合结构“for +名词（代词）+不定式”， 在句中可以做主语、宾语、表语、状语、定语。
This box is too heavy for the little boy to carry.
I have some books for you to read.我有几本书送给你读
That's for you to decide.那个由你来决定。 He stood aside for me to pass.他站到一边让我通过。
注意 … for / of sb to do sth
①形容词easy, difficult, hard, important, necessary, possible, impossible指行为的性质用：for sb. to do sth.。
②形容词right, wrong, brave, careful, careless, clever, wise, stupid, foolish, silly cruel, good, honest, kind, nice,rude ,polite指人的性质和特征，则用of sb. to do sth.。
这种复合结构在句中可作主语、表语、宾语、定语、状语等
It is necessary for me to learn English well.
It’s very kind of you to come to see me.
8.不定式的省略,
1)在两个动词不定式并列使用时，为了避免重复，后面的不定式符号to可省略。
The little girl hardly knew whether to laugh or cry.这小姑娘不知道是哭好还是笑好。
Can you help me to call him and ask him to attend the meeting at 200 p.m.
2)在助动词或情态动词之后，如be going to, used to, have to, ought to, be able to, be about to等。
She must go but you don't have to. 她必须走，但你没有必要。
---Do you think I ought to go to see my doctor
---Yes, I think you ought to. 是的，我想你应该去。
3）在want, decide, like, love, hope, wish, mean, refuse, try等动词之后。
You may go with them if you hope to. 如果你希望的话，你可以和他们一起去。
---Did you go to see the Great Wall
---I wanted to, but I was too busy. 我本来想去的，但我太忙了。
4）．在做宾语补足语的ask, tell, order, advise, persuade, warn, wish, permit, allow, forbid等动词之后。
Don't do anything unless your father tells you to. 除非你父亲叫你去做，不然不要做任何事情。
---May I use your car 我可以用你的汽车吗？
---No, I forbid you to. 不，我禁止你使用。
5）．在对话的答语中的happy, glad, eager, anxious, willing, ready, pleased, afraid等形容词之后。
---Will you lend me a hand ？
---I'm willing to, but I can't now. 我很愿意，但现在不行。
---Would you please come to my birthday party tomorrow？
---I'll be glad to.我很乐意。
提示：如果动词不定式是to be或to have，则一般不省。
--- Did you finish the work你的工作完成了吗？
-- No, but I hoped to have.没有，但我希望已经完成了。
9.不定式“独立主格结构”，在句子中通常起状语的作用。
Such an able man to help you，you will surely succeed sooner or later.
His mother to come tonight，he is busy preparing the dinner.
Many flowers,and grass to be planted,our newly-built school will look even more beautiful.
10. “with、without +名词+不定式”结构
With so much work to do, I shall not be able to go to the cinema with you.
With him to stay in the house, I feel quite safe.有他住在家里，我感到十分安全。
Without anything to eat, he died of hunger.由于没有东西吃，他饿死了。
11.作独立成分 表示说话人的态度，看问题的角度，或者对所叙述的情况进行解释
To be honest ，I don't agree with what you said.
常见不定式独立成分 :
to tell you the truth说老实话
to be frank 坦率地说
to begin with首先
to be brief简言之
to make a long story short长话短说
to be exact精确地说
to say nothing of姑且不说
to conclude总而言之
to be sure诚然，固然
to do him justice说句对他公道的话
so to speak可以这么说
12. 分裂不定式
动词不定式to do偶尔也可在不定式符号to和动词原形之间插入一个副词，构成分裂不定式。
He was too ill to completely carry out that program.他病得太重，不能完成那个项目。
He has made up his mind to once more try this method. 他已经下定决心再试试这个方法。
13．用于感叹句
不定式可用于感叹句，含有惊异、不满、惋惜或赞美等感情色彩。
To think that he should do this!想想，他竟然干出这等事！（表示惊讶）
To think that all the money has been wasted.想想，所有的钱都被浪费掉了！（表示不满）
Oh, God, to see her dance !哦，天哪，看看她的舞蹈！（表示赞美）