不定式的用法

1）不定式有两种，即带to的不定式（a）和不带to的不定式（b）：
a．I’ve come to seek your advice. 我是来向你求教的。
b．What you said made me think. 你的话使我深思。
不带to的不定式和动词原形相同，有人称作 光秃不定式（Bare Infinitive）,不过在大多数情况下不定式都带to。
2）不定式在句中可充当许多成分:
a．构成谓语：
He seems to be in good health.  他似乎身体很好。
b．作主语：
To know everything is to know nothing. 事事皆懂，无一精通。
c．作宾语：
I hope to be back in a couple of days.  我希望两三天就回来。
d．构成复合宾语：
She wanted this meeting to be a successful one. 她希望这次会议成功。
e．作定语：
Do you have anything to say？ 你有什么话要说吗？
f．作状语：
I was delighted to receive your letter. 我很高兴收到你的来信。
g．作表语：
My duty is to get you away,to save you. 我的职责是帮你逃走，更要救你。
3）不定式毕竟还是动词，因而也具有动词的某些特点，如：
a．可以有自己的宾语：
They asked to see my passport. 他们要求查验我的护照。
b．可以有自己的状语：
She told me to go home. 她要我回家。
不定式和它后面的宾语或（和）状语构成不定式短语（下面谈到不定式时也都包含了不定式短语）。
4）不定式有一些不同形式：
              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               ——
完成进行式    to have been doing         ——
5）不定式虽然不能有自己的主语，但在意思上仍有履行这动作的人或物，称为逻辑主语（Logical Subject）。下面句中的黑体词就是不定式的逻辑主语：
She taught me to read. 她教我认字。（我认字）
I’ll be glad to help you. 我将乐于帮助你。（我将帮助你）
当不定式和它的逻辑主语有被动关系（即动作被它做）时，不定式就需要用被动形式：
She was sent there to be trained as an astronaut. 她被派到那里接受宇航员的训练。
不定式前面有时有一个由介词for引导的短语，来表示它的逻辑主语：
The simplest thing is for him to resign. 最简单的办法就是他辞职。

不定式构成谓语有下面几种方式：
1） 不带to的不定式和某些助动词构成谓语。
Will you please call back again in a little while?请过一会儿再打电话过来好吗？
Shall I help you?要不要我帮你。
Would you like me to interpret for you?要不要我来给你当翻译？
I’ll be backi right away.我马上回来。
He won’t tell me his address. 他不肯告诉我他的地址。
I should think so.我想是这样的。
2）不带to的不定式和情态动词构成谓语：
We must keep this in mind.我们必须记住这一点。
How can we convince him?我们怎么才能使他相信？
She might not like the idea.她可能不赞成这个想法。
We needn’t wait for him.我们不必等他了。
How dare you call me a liar?你怎么敢说我是撒谎者？
We’d better wait and see.我们最好等着瞧。
3） 不定式和某些动词构成谓语：
How are you going to solve the problem?你准备怎么解决这个问题？
What time is the plane to take off?飞机什么时候起飞？
You ought to be prepared for the worst.你必须准备应付最坏的情况。
We have (got) to be cautious.我们必须慎重行事。
I’m sorry I haven’t been able to do much.抱歉我没能多帮忙。
We used to work in the same department. 我们过去在一个部门工作。
She happened to live in the same area.她碰巧住在同一个地区。
How did you get to know all this?这一切你是怎么知道的？
He seemed to be doing all right.他似乎情况不错。
You appear to have travelled a lot.你好像走过许多地方。
4） 不定式和某些形容词构成复合谓语：
The plan is bound to succeed.这计划一定会成功。
Madame is sure to be right.夫人肯定是对的。
He is certain to return.他一定会回来。
He is much more likely to be in Spain. 他更可能在西班牙。
He is unlikely to arrive before 1:00 p.m.他下午一点前到达的可能性不大。
He was apt to become excited.他很容易激动。
The talk is due to start on Monday.会议定于星期一开始。
5）不定式和某些被动结构构成复合谓语：
He is said to have been in China many times.据说他曾经多次到过中国。
Another spaceship is believed to have landed on Mars.据信又有一艘宇宙飞船在火星上着陆了。
This was thought to be impossible.过去这被认为是不可能的。
His situation was considered to be dangerous.他的处境被认为是很危险的。
He is known to be a great artist. 大家都知道他是一位伟大的画家。
You are not supposed to know that. 你不应当知道此事。
The situation there is reported to be deteriorating.据报道那里的形势正在恶化。
You are expected to speak at the meeting.大家期待你在会上发言。
不定式可以作主语，如：
To compromise appears advisable.妥协似乎是明智的。
To lean out of  the window is dangerous。把头伸出窗外是危险的。
To stop the work now seems implssible.现在把这工作停下来似乎已不可能。
To ignore this might have serious consequences.忽略这一点可能会有严重后果。
To err is human,to forgive,divine.（谚）犯错误人皆难免，宽恕才难能可贵。
但在更多情况下都用it作先行主语，而把不定式这个真正主语放到句子后部去，这样可主语不至显得太长，避免头重脚轻的现象。常见的这类句子有下面几种：
 1）It +be+形容词+不定式（斜体部分为真正的主语）：
It’s hard(difficult) to say which is better.很难说哪个更好。
It’s foolish(silly) to act like that.这样做是愚蠢的。
Is it easy to learn a foreign language?学外语容易吗？
It is not necessary to do all these exercises.没有必要做所有的这些练习。
It’s impossible to finish the job in one day.一天完成这项工作是不可能的。
It’s so good(nice) to talk to you.和你谈话真好。
It isn’t right to waste so much money on it.在这上面白花这么多钱是不对的。
It is essential(important) to know all the facts.掌握所有事实至关重要。
It’s still possible to catch the train.还有可能赶上火车。
It’s advisable to revise the plan.修改计划是明智的。
It is wrong to steal.偷窃时错误的。
2）It +名词+ 不定式：
It’s an honour to meet you.见到你很荣幸。
It’s our duty to obey the law.遵守法律是我们的责任。
I think it’s a pity to waste so much money.我想浪费这么多钱是遗憾的。
It was great fun to have a picnic there.在那里野餐很有意思。
It’s a good habit to eat slowly. 细嚼慢咽是好习惯。
It’s a shame to deceive your friends. 骗你的朋友是很可耻的。
It’s a great pleasure to work with you. 和你们一起工作非常愉快。
It’s my wish to do something for the public. 为公众做些事是我的愿望。
3） It +动词（宾语）+不定式：
It cost a lot of money to build this museum. 盖这座博物馆花了很多钱。
How long does it take to fly across the Pacific Ocean?飞渡太平洋要多少时间？
It requires patience to be a teacher.当老师要有耐心。
It amused me to hear these jokes.听到这些笑话我很开心。
It would take ages to really master a language.要真正掌握一种语言需要花很长时间。
It takes two to make a quarrel.(谚)吵架要有两个人。
It made us very angry to hear him talk like that.听他这样讲话让我们很生气。
It feels good to be out here for a while.出来在这待一会是挺惬意的。
What harm can it do to give advice?给人出主意有什么不好？
4） It +be +介词短语+不定式：
It’s against my principles to collaborate with them.和他们合作违反我的原则。
It’s beyond me to explain these.要解释这些我力所不及。
It’s not within my power to change his view.要改变他的观点非我所能。
It would be beneath him to accept such a job.接受这份工作会有失他的身份。
It is just like you to be always ready to help a friend.随时准备帮助朋友正是你的本色。

1）不定式作宾语时特别多，许多动词都可跟这种宾语：
He agreed to pay $ 4,000 for the car.他同意出四千元买这辆车。
They failed to fulfil the plan.他们没能完成计划。
We managed to put the fire out.我们终于把火扑灭了。
They are preparing to build a freeway between the two cities.他们正准备在两座城市之间建一条高速公路。
She preferred to stay behind.她宁愿留下。
The soldiers refused to surrender.士兵们拒不投降。
She volunteered to go and work in the northwest.她志愿到西北地区工作。
We can’t afford to stay at a five-star hotel.我们住不起五星级酒店。
Don’t bother(trouble)to answer the letter personally.不必费事亲自回信。
You must learn to look after yourself.你必须学着照顾自己。
常见的这类动词有：
afford       agree        aim        arrange       ask       attempt
bear         begin        bother     care          choose    claim
consent      continue     dare       decide        decline   demand
deserve      desire       determine  endeavour     except    fail
forget       guarantee    hate       help          hesitate   hope
intend       learn        like       long          love       manage 
mean         need         neglect    offer         plan       pledge
prefer       prepare      pretend    promise       prove      refuse
remember     resolve      scorn      seek          strive     swear
threaten     trouble      try        undertake     volunteer  vote
vow           wait        want       wish
2)不定式有时和一连接代（副）词一道构成宾语：
He discovered how to open the  safe. 他发现了开保险箱的方法。
I’ll ask him how to operate the machine.我来问他怎样开这机器。
She couldn’t think what to say. 她想不出该说什么。
He taught me  how to swim. 他教我怎么游泳？
Have you decided what to do next? 下一步干什么你决定了吗？
You must learn how to be patient.你必须学会怎样保持耐心。
We have to find out where to buy food cheaply.我们得打听一下哪里能买到便宜食品。
Do you remember which way to get there? 你记得到那里怎样走吗？
I forgot how to say it in English.我忘了这话英语怎么说了。
He didn’t know whether to laugh or to cry. 他感到啼笑皆非。
She wondered whether to turn left or right.她不知道该向左拐还是右拐。
3） 间或还可用这种结构作介词宾语：
He wrote a book on how to protect the environment.他写了一本关于环保的书。
They were worried about how to find  the necessary  equipment.他们为如何找到所需设备而发愁。
Then there is the problem of what courses  to offer.接着就是开些什么课程的问题。
We  also had a discussion about what investments to make.我们还讨论了应作哪些投资。
4） 偶尔可使用一个先行词it作形式上的宾语，而把不定式转放到句子后部去：
I have long had it in mind to answer your letter.好久以来我一直想回你的信。
She took it on herself  to apologize to me.她亲自来向我道歉。

1）许多动词可跟一个由“名词（代词）+不定式”构成的复合宾语：
I ask George to convey my best wishes to his mother.我请乔治向他母亲问好。
My boss told me to type out two letters.我的老板让我打两封信。
He likes(wants) the students to eat well.他愿意学生们吃得好。
He begged her to forgive him.他恳求她宽恕他。
I expected him to arrive on Saturday.我估计他星期六到达。
She encouraged me to try again.她鼓励我再试一次。
They forbade her to leave the country.他们禁止她出境。
They persuaded him to give up smoking.他们劝他戒了烟。
They are training these dogs to sniff out drugs.他们在训练这些犬嗅出毒品。
These glasses enable me to see better.这副眼镜能使我看得清楚一些。
Please remind me to post this letter. 请提醒我发这封信。
常见的这类动词有：
advise         allow       ask       beg        bride       cause 
challenge      command     compel    convince   direct      enable
encourage      expect      forbid    force      induce      instruct
invite         oblige      order     permit     persuade    press
recommend      remind      request   require    teach       tell
tempt          train       urge      want       warn
2）有些动词可跟带有to be的复合宾语，如：
I consider  him to  be  the best candidate.我认为他是最佳候选人。
I supposed him to be away from home.我想他不在家。
They believed these principles to be universally true.他们认为这些原则是普遍适用的。
They declared it to be a province of Morocco.他们宣布这是墨西哥的一个省。
We discovered him to be quite untrustworthy.我们发现他很不可信赖。
He felt that to be the highest praise.他感到这是最高的赞美。
She found the Chinese people to be happy and cheerful.她发现中国人非常幸福愉快。
He judged them to be the best work he had yet done.他认为它们是他迄今写的最好的作品。
I know him to be a liar. 我知道他是个爱说谎的人。
We have shown the story to be false.我们已经表明这种说法是不真实的。
这类动词后的不定式有时可以是完成形式或进行形式，此时的不定式不是be：
His record shows him to have worked hard at school.他的成绩单表明他上学时很勤奋。
I considered him to have acted disgracefully.我认为他的表现很可耻。
I judge them to have finished.我估计他们已经干完了。
They knew the man to have been a spy.他们知道那人过去当过间谍。
They believed him to be hiding somewhere.他们认为他躲在什么地方。
3）跟复合宾语的动词有时可用于被动结构，这时可说形成一种复合谓语：
She was told to wait at the door.他们让她在门口等着。
You are not expected to work such long hours.并不指望你工作这么长时间。
This vase is estimated to be 2,000 years old. 这花瓶估计已有两千年的历史。
He is known to be bonest.大家知道他是诚实的。
He was thought to be a great novelist.他被认为是一位伟大的小说家。
He was asked to testify in Congress.他被请到国会作证。
He was warned not to go there.有人警告他不要去那里。
They were forced to pay heavy taxes.他们被迫交纳重税。
She was forbidden to stay out after midnight.禁止她午夜后在外逗留。
They were not allowed to form secret societies.不允许他们秘密结社。
这类结构中的不定式可用完成式或进行式：
He was known to have worked for the French.. 大家都知道他曾经给法国人干过事。
They are believed to have found a cure for cancer. 据信他们发现了一种治疗癌症的方法。
He was rumoured to have married a widow. 谣传他和一个寡妇结了婚。
He is said to have won another gold medal.据说他又获得一枚金牌。
The allied forces were reported to be pushing towards Berlin.据报导盟军正在向柏林推进。
They were thought to be hiding in the woods.人们认为他们躲在树林里。
He is supposed to be washing the car.此刻他应当在洗车。
She is believed to be living in Tokyo.据信她现在住在东京。
4) 有些动词可跟由不带to的不定式构成的复合宾语：
Did you see anyone enter the house?你看见什么人进屋了吗？
I hear her lock the door.我听见她锁门了。
She won’t let me do it.她不让我做这事。
He made me move the car.他让我把车移动一下。
We watched the children skip rope.我们看孩子们跳绳。
Did you notice a man come in?你注意到有个人进来吗？
I won’t have  him cheat me like that.我不会让他这样骗我。
I felt something crawl(ing) up my arm..我感到有东西顺着我手臂往上爬。
但这类句子变成被动结构时，不定式前要加to：
A child was seen to enter the building.有人看见一个孩子进了大楼。
She was often heard to sing this song.人们常常听见她唱歌。
He was often made to recite poem in class. 老师经常让他在课堂上背诵诗句。
在listen和look at后面也可跟这种结构：
He listened to us retell stories.他听我们讲故事。
Look at the girls dance!瞧那些女孩子跳舞。
在help后的不定式可加to，也可不加to（美国人不加to时较多），但被动结构中要加to：
I’ll help you (to) push the cart.我来帮你推车。
You’ll be helped to fulfill the task.有人将帮助你完成这项任务。
5）有些“动词+介词”结构后也可跟由不定式构成的复合宾语：
He shouted to me to come over.他喊我过去。
She appealed to women to participate in the struggle.她呼吁妇女参加这一斗争。
The teacher called on me to answer this question.]老师叫我回答这个问题。
He pleaded with her to go back.他恳求她回去。
She longed for him to ask her out.她希望他邀她外出。
I am counting on you to help me through.我指望你帮我度过难关。
He relied on his subordinate to prepare the report.他依靠他的下属来准备这份报告。
I depend on you to do it.我指靠你来办这事。
We hope to prevail upon her to attend the concert.我们希望劝动她来听音乐会。
She wouldn’t care for the man to be her husband.她不愿意那个男人当她的丈夫。
He waited for it to be light.她等着天亮。
6） 某些动词后可跟先行词it，借此把构成复合宾语的不定式放在后部：
I find it easy to get on with you。我发现和吉姆相处很容易。
He thought it best to be on his guard.他认为最好小心提防。
The judge deemed it inadvisable to hear the appeal.法官认为听取这个上诉不明智。
All this made it hard for her to make a decision.这一切使她难于作出决定。
He didn’t feel it necesary  to mention this to her.他感到没有必要向她提及此事。
She regarded it as important to win the competition.她认为赢得这场比赛很重要。
Do you think it worthwhile to visit him?你认为拜访他值得吗？
We don’t consider it possible to set back the clock of history.我们认为要使历史的时针倒转是不可能的。
We consider it our duty to safeguard world peace.我们认为保卫世界和平时我们的职责。
He made it a rule to walk two miles a day.他规定自己每天走两英里路。

1）不定式常可以用来修饰一样东西：
We have a lot of thing to do today.今天我们有好多事要做。
Do you have any suggestions to offer?你有什么建议要提吗？
I’ve got two letters to write tonight.今晚我有两份信要写。
He made a device to make the door shut by itself.他制作了一个让门自动关闭的装置。
Would you like something to drink?你想喝点什么。
It’s a difficult question to answer.这是个难以回答的问题。
Please give me a book to read.请给我一本书看。
I’ll find you something to eat.我来给你找点东西吃。
I want a machine to answer the phone.我要一台电话答录机。
This is not the right attitude to take.这不是应当采取的正确态度。
It seems to be the only thing to da.这似乎是唯一可做的事。
We were looking for somewhere to live.我们在找一个地方住。
I need a case to keep my compact discs.我需要一个盒子装我的激光唱盘。
There is plenty to do here.这儿有很多事要做。
不定式有时需用被动形式：
There are a lot of things to be done.有很多事情要做。
He is dead.There’s nothing to be done now.他人已死了，无法可想了。
Where are the things to be taken to her？要带给她的东西在哪里？
On which page is the question to be answered?要回答的问题在哪一页？
Are you going to the banquet to be given at the consulate?你准备参加领事馆举行的宴会吗？
2）不定式还可用来修饰人:
He was the first guest to arrive.他是第一个到达的客人。
He was the second man to hear the news.他是第二个听到这消息的人。
She was the only one to survive the crash.她是这次空难中唯一的幸存者。
I want someone to talk to.我想找个人谈。
Miss Brown was the next person to rise to speak.布朗小姐是下一个起来发言的人。
He is not a man to bow before difficulties.他不是一个向困难低头的人。
You’re the right person to do this job.你是做这工作的合适人选。
We need twenty more people to work in the boat我们还需要二十个人在船上工作。.
You’re the only person to complain.你是唯一抱怨的人。
He was a brave man to do what he did.他是个勇者才有这样的行为。
不定式有时需用被动形式：
She was the first person to be awarded this prize.她是第一个获得这奖项的人。
He was the second man to be killed this way.他是第二个这样被杀害的人。
She will be a suitable person to be given this job.她是适合给予这项工作的人。
He was the only foreigner to be given such an honour.他是唯一被授予这项荣誉的外国人。
3）在不少名词后可用不定式作定语：
It’s time to go to bed.该睡觉了。
There’s no reason to doubt his word.没有理由怀疑他的话。
I haven’t had a chance to think yet.我还没有机会思考。
They have now an opportunity to air their views.现在他们有机会发表各自的看法了。
To scare a bird is not the way to catch it.（谚）吓唬鸟儿不是捕鸟的法子。
There is no need to worry at all.根本用不着担心。
His efforts to get her back were vain.他争取她回来的努力都白费了。
Jane expressed a wish to earn her own living.简表示愿意自谋生计。
He has a tendency to forget things.他容易忘事。
I have a right to know.我有权知道。
He has a burning ambition to become famous.他一心想成名。
4） 有些名词的同根词常跟不定式，因而它也常跟不定式作定语：
I don’t trust his promise to come for a visit.我不相信他来访的诺言。
（比较：He promised to come for a visit.）
He said he had no plans to increase taxes.他说他没有要增税的计划。
（比较：He didn’t plan to increase taxes。）
He made an attempt to stand up.他试图站起来。
（比较：He attempted to stand up.）
Their offer to assist in the work was not taken seriously.他们提出协助这项工作并未受到认真对待。
(比较：They offered to assist in the work.。)
His decision to resign was welcomed by the opposition.他辞职的决定受到反对党的欢迎。
（比较：He decided to resign.）
She persisted in her refusal to go home.她坚持不肯回家。
（比较：She refused to go home.）
His failure to answer questions made the police suspicious.他答不出问题使警察产生怀疑。
（比较：He failed to answer questions.）
His ability to get on with people is his chief asset.他能和人相处是他主要的优点。
（比较：He is able to get on with people.）
Her anxiety to succeed led her to work hard.她迫切想成功，这促使她努力工作。
（比较：She was anxious to succeed.）
I was surprised at his eagerness to return,他急切想回去使我感到惊讶。
（比较：He was eager to return.）
In February they announced their willingness to send delegates to the conference.二月里他们宣布愿意派代表参加会议。
（比较：They were willing to send delegates to the conference.）
They showed a surprising readiness to accept the proposal.他们表示乐意接受这个建议，这一举动令人吃惊。
（比较：They were ready to accept the proposal.）
5)有时一个不定式（短语）的作用接近于一个定语从句（大多表示要发生的事）：
That will be the right procedure to follow(=you should follow).这将是应遵循的正当程序。
Soup,and then steak to follow,please.请先上汤，然后上牛排。
She was quiet for days to come. 此后许多天她都沉默无语。
That would be a rash step to take. 那可能是一个鲁莽的举动。
They were invited to the dance to take place after the wedding他们被邀请参加婚礼后的舞会。.
Are you going to the banquet to be held on Friday at the embassy? 你要去参加星期五在大使馆举行的宴会吗？
另外，不定式还可以和关系代词which连用作定语：
She must have time in which to pack..她必须有时间收拾行李。
They would raise some money with which to buy medicines.他们将筹集一些钱购买药品。
He also had a revolver with which to defend himself.他还有一把防身用的左轮手枪。
He only had long nights in which to study.他只有漫漫长夜可用来学习。
在个别名词后可用不定式作同位语（说明前面这个词的内容）：
Then came the order to evacuate the city.接着传来撤出城市的命令。
They had received instructions to watch him.他们接到指示要监视他。

不定式作状语的时候很多，主要有下面这几种情况：
1） 用于“be+形容词+不定式”这种结构：
a． be+表示情绪的形容词+不定式：
She was eager to see her friends.她急于见到她的朋友们。
I am afraid to tell her.我很害怕告诉她。
I was sorry to hear that you were ill.听说你病了我很难过。
Helen was pleased to see him.海伦见到他很高兴。
I’m proud to be a Chinese.我为自己是个中国人而骄傲。
She was surprised to see George walk in.她惊讶地看到乔治走进来。
He was very disappointed to hear it.听了这话他感到很失望。
I’m ashamed to have to trouble you.我很惭愧不得不麻烦你。
She was keen to go.她非常想去。
I shall be glad to help you find a new job.我将乐于帮你找一份新工作。
b．be+表示状态的形容词+不定式：
I am not ready to go back to work yet.我还不准备回去上班。
Gray was prepared to leave the country.格蕾已准备好处境。
He was determined to teach them a lesson.他决心给他们一个教训。
She was careful to make no observation.她很谨慎，不作任何评价。
He was quick to offer his counter-proposal.他迅速提出反建议。
He was curious to know what was happening in the office.他好奇的想知道办公室里发生的事。
She’s not fit to live by herself.她不适合一个人住。
She was free to go where she lived.她想去哪里就可以去哪里。
He was lucky to find such a good job.他很幸运找到这样好的工作。
b． be+表示品质等的形容词+不定式：
He was brave to act like that.他这样做很勇敢。
You were right to do what you did.你这样做是对的。
I was wrong to speak to her about it.我和她谈及此事是错误的。
You were foolish to act like that.你这样做很愚蠢。
He was generous to give you so much money.他很大方，给你这么多钱。
She’s interesting to be with.和她说话很有意思。
He was amusing to be with.和他在一起很有趣。
Rose will be easy to deal with.罗莎会很容易对付。
She was hard (difficult)to convince.她很难说服。
这类句子有时可以表示“物”的名词作主语：
The fruit is not fit to eat.这种果子不宜食用。
Its seeds are particularly good to eat.它结的籽特别好吃。
Polyester is easy to iron.涤纶很容易熨烫。
Do you think the water is safe to drink?你认为这水喝起来安全吗？
The question is difficult to answer.这问题很难回答。
2）不定式可用作状语，表示目的（a）、原因（b）、结果（c）等：
a．A friend of mine came to see me last night.昨晚有个朋友来看我。
A gentleman stopped to talk to me.一位先生停下来和我谈话。
We slept together to keep warm.我们睡在一起以保证暖和。
To do good work,one must have the proper tools.要干出像样的活得有合适的工具。
As if to remind him,the church clock struck eleven.彷佛是要提醒他，教堂的钟敲了十一点。
b．I rejoice to hear that you are well again.听说你痊愈了，我很高兴。
She shuddered to think of those days.想到那些岁月她不寒而栗。
We jumped with joy to hear it。听到这消息我们都高兴的跳了起来。
To hear him talk in that manner,you would think he’s a foreigner.听他这样讲话你会以为他是个外国人。
c．What have I said to make you so angry?我说了什么话使你这么生气？
The curtains parted,to reveal a market scene.帷幕拉开，露出一个集市的场景。
He left,never to return.他走了，再也没有回来。
She lived to be 100.她活到了100岁。
3）在许多句型中可用不定式作状语：
He was so careless as to leave his car unlocked.他如此粗心大意，车门都没锁就走了。
Would you be so good as to forward my letters to me?劳驾把我的信转给我好吗？
Go in quietly so as not to wake the baby.悄悄进去，别把宝宝吵醒。
He had sacrificed so much in order to avoid pain.他牺牲这么大为的是避免痛苦。
His behavior is such as to make his friends angry.他这样的行为惹恼了他的朋友们。
Would you be good enough to close the door.可否劳驾关门。
She isn’t old enough to travel by herself.她年纪尚小，不能独自去旅行。
You are too young to understand.你太年轻不能理解。
It was too late to do anything now.现在做什么都已为时太晚。
4）有些不定式可用来修饰整个句子，因而可以称作句子状语（Sentence Adverbial）：
To be honest,I just don’t like him.说实话，我就是不喜欢他。
To be fair(to him),he wasn’t entirely to blame.说良心话，不能全怪他。
To tell you the truth ,I’ve never met him.说真的，我从来没有见过他。
To be frank,you’re a bad driver.坦率的说，你开车技术不行。
To cut a long story short,we said,“No!” 长话短说，我们回绝了。
He’s a nice person ,to be sure.毫无疑问，他是一个好人。
To put it in another way,she was sweet-tempered,换句话说，她脾气非常好。
To begin with,it’s too cold.Besides,we’ve no money.首先，天太冷，再者我们也没有钱。

1）不定式有时可用作表语，说明主语的具体内容：
Her ambition was to be a film star.她的志向是当电影明星。
Our aim is to make the students’ speech comprehensible.我们的目标是让学生讲的话能被人听懂。
Mary’s task is to set the table.玛丽的任务是摆桌子。
His goal is to be a scientist.他的目标是当科学家。
My only wish is to do something for the public.我唯一的愿望是为公众做    些事。
The first step will be to get a job in some office.第一步就是找一份办公室的工作。
The purpose of this meeting is to elect a new captain.这次会议的目的是选一名新队长。
Your mistake was to sign that letter.你的错误时签署了那封信。
2）不定式作表语还可以表示其他东西（如目的等）：
This wall is to keep people out of the garden.这堵墙为的是不让人到花园里来。
The thing now is to get ahead.当务之急是要取得进展。
The problem was to find the right people for the job.问题是要找到合适的人来干这工作。
The point is to win at any cost.要紧的是不惜一切代价取得胜利。
The important thing is not to wrong any person.重要的是不要冤枉人任何人。
All you have to do is to listen.你只要听着就行了。
My plan was to go from Cornwall to Glasgow.我的计划是从康沃尔到格拉斯哥。

1）不定式的完成形式：
当不定式表示的动作在谓语所表示情况之前发生，就需要用完成形式：
a．I happened to have been there once. 我碰巧到过那里一次。
She seemed to have lost her patience.她似乎已失去耐心。
You are supposed(ought)to have heard of it.你应该已听说此事。
b．What a mistake it is to have come here!来了这里是个多大的错啊！
It would have been amusing to have joined them.参加了他们的活动会很有意思的。
It was my intention to have  stopped there.在那里停下来是我本来的意图。
c．They claimed to have shot down five planes.他们声称打下了五架敌机。
She pretended not to have seen him.她假装没看见他。
I remember to have told you about it.我记得告诉过你这件事。
d．I am sorry to have given you so much trouble.对不起给了你这么多麻烦。
He was pleased to have made your acquaintance.他很高兴认识了你。
He felt ashamed to have done such a thing.他做了这样的事感到很惭愧。
e．He was known to have worked for the International Olympic Committee.大家知道他曾为国际奥林委工作过。
They are believed to have discussed the problem.据信他们曾讨论过这个问题。
She is rumoured to have eloped with a priest.谣传他和一个牧师私奔了。
这类不定式可以在句子中构成谓语（a），充当主语（b），宾语（c），状语（d），还可构成另一类复合谓语，即复合宾语的被动结构（e）。
2）不定式的进行形式：
当不定式表示一个正在进行的动作时需要用进行形式：
a．He seemed to be dreaming.他似乎在做梦。
She happened to be travalling in that area.她恰好在这个地区旅游。
You ought to be reviewing your lessons now.你现在应当在复习功课。
b. It’s strange to be sleeping in this house again.真奇怪又要在这屋子里睡觉了。
It's a delightful experience to be touring the lake district.在湖区旅游时一段愉快的经历。
What a shame (it is )to be washing your time like that.把你的时间这样浪费掉真是不好意思。
c. The man pretended to be weaving.那人假装在织布。
I really hope to be working with you.我的确希望和你们在一起工作。
I hate to be quarreling with her.我不愿意和她吵架。
d．I was pleased to be talking with them.我很高兴和他们在一起谈话。
Are you glad to be going home?你高兴回家吗？
She was happy to be earning her own living.她很高兴能自食其力。
e.  He is believed to be living in Mexico.据信他住在墨西哥。
Thousands were reported to be working in concentration camps.据报道那时有数以千计的人在集中营干活。
He is thought to be hiding in the woods.人们认为他躲藏在林子里。
He appears to have been waiting a long time. 他似乎已等了好长时间。
He pretended to have been studying.她假装一直在学习。
She is said to have been doing this work for twenty years.据说她干这工作已二十年了。
3）不定式的被动形式：
 不定式有时需用被动形式：
a．She ought to be praised for her heroic deeds. 她的英勇行为应受赞扬。
The parcel has to be sent by air mail.这个包裹得寄航空。
The election was due to be held in November.选举定于十一月举行。
b.  It’s an honour to be awarded a scholarship.被颁给奖学金是一种荣耀。
It’s just my luck to be caught in the storm.碰上暴风雨是我倒霉。
It was his good fortune not to have been injured.他很幸运没有受伤。
c.  She asked to be given an opportunity to try her method.她要求给她机会试验她的方法。
They wanted to be better treated.他们希望受到更好的对待。
He hates to be flattered.讨厌受人恭维。
d. These are the major problems to be discussed at the meeting .这些事会上要讨论的主要问题。
Are you going to the conference to be held in June?你要去参加六月举行的大会吗？
She was the first one to be asked to speak.她是第一个被邀请发言的人。
e. She went to the hospital to be inoculated.她到医院去打预防针。
She left the city,never to be seen again.她离开了这座城市，再也没有人见到过她。
He was sent abroad to be educated.他被派去国外受教育。

1）每个不定式可以有其逻辑主语，它可能是句子的主语或宾语，如：
I had a lot of letters to write.(I 是to write的逻辑主语)
I’ll give you something to read.（you 是to read的逻辑主语）
当句中没有适当的词时可作不定式逻辑主语时，可以借助一个由for引导的短语来表示它的逻辑主语：
Here are some books for you to read on the way.这儿有几本书给你在路上看。
2）这种短语在句中可以和不定式一道起作用。如：
a．作主语：
It won’t be easy for you to find a new job.你想找新工作不会很容易。
It isn’t right for people to marry for money.人们为金钱结婚是不对的。
For an old man to run fast is dangerous.老年人快跑是危险的。
b. 作定语：
It’s time for you to reconsider your decision.现在是你重新考虑你的决定的时候了。
There’s no reason for us to doubt his words.我们没有理由怀疑他的话。
It’s a good opportunity for us to exchange our experience.这是我们交流经验的好机会。
c.  作状语：
He stood aside for her to pass.他站到一边让她过去。
Please do send for Mummy to come too.请一定派人把妈妈叫来。
Her circumstances had never been good enough for her hopes to be realized.她的境况从来没有好到使她的希望成为现实。
d. 作表语：
The simplest thing is for him to resign at once.最简单的办法是他马上辞职。
What I want is for you to talk to Lanny.我希望的是你和兰尼谈一谈。
It’s for you to decide what we should do next.得由你来决定我们下一步该做什么。
3） 在少数情况下可用of引导的短语。表示不定式的逻辑主语：
It was kind of you(You were kind)to help me.难得你好心帮助我们。
It was silly of you(You are silly)to trust such a man.你太愚蠢竟然信赖这样一个人。
It was selfish of him not to do anything for the orphans.他很自私不愿为孤儿们做任何事。
It was generous of you to contribute so much money.你很大方捐出这么多钱。
It’s unfair of him to say such things about her.他说她这样的话是不公道的。
It was annoying of him to damage my car. 他损坏了我的车让人生气。
只有那些作表语的形容词能修饰人时，才能在不定式前用of 引导的短语，否则还是应当用for引导的短语来表示不定式的逻辑主语。

1）不定式的省略：
为了避免重复，有时不定式中的主要动词可以省略，只剩下to：
Would you like to come with us?——Yes,I’d love to.你愿意和我们一道去吗？——愿意。
Did you get a ticket?——No,I tried to, but there weren’t any left.你买到票了吗？——没有，我去买过，但都卖光了。
Do you often play bridge?——I used to,but not now.你经常打桥牌吗？——过去常打，但现在不打了。
Have you cleaned the windows?——No,but I am just going to.你擦窗子了吗？——没有，不过我正要去擦。
I wanted to get in touch with her but wasn’t able to.我想和她联系，但没能联系上。
You can go if you want to.你如果想去可以去。
You don’t know her?You ought to.你不认识她？你该认识她的。
Will you join me in a walk?——I’d be glad to.你愿意和我一道去散散吗？——好呀。
在个别情况下to可保留，也可一道省略：
He says he will come as soon as he has got a chance(to).他说他一有机会就来。
They won’t encourage you to do it even if you have the time(to).他们不会鼓励你这样做，即使你有时间（这样做）。
She may go if she likes(to).她如果想去可以去。
在用不定式作表语时，to有时也可省略，如：
All I did was(to)press the button.我只是按了一下电钮。
What you have to do is (to) fill in the questionaire.你所要做的是把问卷填好。
在used to,be going to,mean to, ought to ,try to ,plan to等结构后，当不定式省略时，to通常是保留的。
2）并列的不定式：
当有两个或更多不定式并列使用时，通常只在第一个不定式前加to，在后面的不定式前to常略：
We ought to read more and have more practice.我们应多读多练习。
She told us to stay at home and wait till she came back.她让我们留在家里等她回来。
I’d like to stay with you ,help you and learn from you.我愿意留在你身边，帮助你并向你学习。
但如果二者有对比关系，每个不定式前都应带to：
To try and fail is better than not to try at all.尝试而失败也比不尝试好。
He hasn’t decided whether to quit or to stay.他还没有决定是去还是留。
To go or not to go ,it’s a question.去还是不去是一个问题。
3） 分裂不定式
有时to和后面的动词间可插入一个副词：
They have started a drive to further improve  the miners’ working conditions.他们开始作一番努力来进一步改善矿工们的工作条件。
He was too ill to really carry out his duty.他病的太重，不能切实履行他的职责。
He likes to half close his eyes.他喜欢半闭着眼睛。
Mother asks you to kindly come over to see us tonight,妈妈请你今晚劳驾到我们家来一趟。
这称为分裂不定式（Split Information）,这种用法在口语中最好避免。如可能，可以把副词放后面去，如to completely cover the floor可改为tocover the floor completely，to unduly alarm people可改为to alarm people unduly。
4） 在个别情况下，可用不定式构成或引导一个句子：
a． 不带to的不定式：
Why bother?干吗费这个事？
Why worry about such trifles?干吗为这些小事烦心？
Why not wait for a couple more days?干吗不再等上一两天？
Why not do it right now?干吗不现在就干？
b． 带to的不定式：
To think he would come to anything like that!没想到他竟是这样的下场！
And to think that I trusted him!没想到我竟然信任了他！
To think of his not knowing anything about it没想到他对此竟一无所知。

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。

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。
 

    "Why not +动词原形"表达向某人提出建议，翻译为："为什么不……?" "干吗不……?"
例如：
　　　Why not take a holiday?
　　　干吗不去度假?