1、定义（语态）动词和参与此动作的主语之间关系的一个术语。当主语是动作的发起者（或之一）时，称为主动语态；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：Its a great honour to be invited to Marys birthday party.（不定式作主语是被动语态to be invited是被邀请）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 m
2、e 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）My work is to clean the room every day.（不定式作表语）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：There is nothing to do now.( We have nothing to
3、 do now.) There is nothing to be done now.(We can do nothing now.)形式1) 现在式：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。一般为：动词+ to do sthHe seems to know this.I hope to see you again. = I hope that Ill see you again.我希望再见到你。2) 完成式：表示的动作发生在谓语动词表示的动作之前。Im sorry to have given you so much trouble.He seems
4、 to have caught a cold.3)进行式：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)完成进行式：She is known to have been wreaking on the problem for many years.一般在表示情绪的动词后加to do也表将来疑问词疑问词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：When to leave for London has not been decided y
5、et. （不定式在句子中做主语）Mr. Smith didnt know whether to leave or stay there. （不定式在句子中做宾语）I asked Professor Xu how to learn English well. （不定式在句子中做直接宾语）The 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：When we shall leavehow Icould learn经常在这种结构中使用的动词有：consider,decide
6、,discover,explain,find out,forget,hear,know,lea rn,observe,understand,wonder等。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.骑自行车到那儿将花费我们半个小时。To make up for lost time is not possible.要弥补失去的时光是不可能的。To lean out of the window is dangerous.身子探出窗外很危险。To sav
7、e money now seems impossible.现在好像不可能存钱。(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：It+be+名词+to doIts our duty to take good care of the old.照顾老人是我们的责任。It is an offence to drop litter in the street.在马路上乱丢废物是违章的。It takes sb+some time+to doHow long did it take you to finish the work?你花了多少时间来完成这项工作？It+be+形容词+fo
8、r sb+to doIt is difficult for us to finish writing the composition in a quarter of an hour.我们难以在四分之一小时内完成这篇作文。It is stupid of you to write down everything (that) the teacher says.你把老师说的所有东西都记下来的行为是很愚蠢的。It seems(appears)+形容词+to doIt seemed impossible to save money.在句型中，常用表示客观情况的形容词，如：difficult,easy,h
9、ard,important,impossible,necessary 等；在句型中，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：Its kind of you to help me with my English.=You are kind to help me with my English.It + 不定式结构可位于believe/consider/discover
10、/expect/find/think和wonder之后He thought it would be safer to go by train.他认为乘火车比较安全。He will find it is hard to make friends.他会感觉到交朋友困难。不定式的完成式也可作句子的主语To have made the same mistake twice was unforgivable.两次犯同样的错误是不可原谅的。It is better to have loved and lost than never to have loved at all.爱过而后失去了爱，比从未爱过要好
11、。(3)举例（1） Its 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 enoughIts so nice to hear your voice.听到你的声音真高兴。Its necessary for you to lock the car when you do not use it.当你不用车
12、的时候，锁车是有必要的。（2） Its 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，a
13、ppear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.眼见为实。(错)It is to believe to see.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），de
14、mand（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（预示），undertake（承诺），volunteer（自愿做），vow
15、（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,tellPlease show us how to do that. 请演示给我们如何去做。There
16、 are so many kinds of tape-recorders on sale that I cant 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。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
17、 foreign language well.He feels it his duty to help the poor.I find it difficult to learn English well.作补语1) 动词+宾语+不定式(to do)常见动词：advise，allow，believe，cause，challenge，compel，declare，encourage，forbid，force，find，hire，induce，instruct，invite，like，order，permit，persuade，remind，request，require，select，send，
18、suppose，tell，train，urge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。2) to + be 的不定式结构，作补语的动词。常见动词：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),unde
19、rstandWe 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 +形容词常见动词：Seem,appear,be said,be supposed,be believed,be thought,be known,be reported,hope, wish,desire,want,plan,expect,meanThe book is believed to be uninteresting.人们认为这本书没什么意思。4)there be+不定式常见动词：believe,exp
20、ect,intend,like,love,mean,prefer,want,wish,undrstandWe didnt 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。5)秃头不定式作补语秃头不定式， 即不带“to”的不定式，其语法功能一般在句子中作宾语
21、的补语（宾语补足语）。用秃头不定式作宾语补足语的常用动词如下：口诀：“五看、三使役“，“两听、一感”要记住，若是“宾补”变“主补”，主补“to”字不能无。动词let属例外，其宾补/主补“to”均无。说明：五看-see/watch/notice/observe/look at；三使役-have/make/let；两听-hear/listen to；一感-feel。例句：I often see him go to school on foot.(秃头不定式作宾语补足语) He is often seen to go to school on foot.(不定式作主语补足语，要带“to”) Let
22、him try again.- He is let try again.(let的主补与宾补均用秃头不定式)Find 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.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。To be kind to the enemy is
23、 to be cruel to the people.My chief purpose is to point out the difficulties of the matter.What 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）。当主语是aim,duty,hope,idea,mista ke,plan,purpose,suggestion等为中心词的名词词组（例）时，或以what引导的名词性分句（例），不定 式说明主语的内容。Our work is serving the people.Wh
24、at he likes is taking a walk after supper.The story told by Mr.Wang is interesting.句动名词作表语，与主语部分可以转换，如Serving thepeople is our work,而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。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 bu
25、s.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Im glad to see you.典型例题The chair looks rather hard,but in fact it is very comfortable to _.A. sitB. sit onC. be seatD. be sa
26、t 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。作定语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：The next train to arrive is from Washington.Do you have anything to be taken to your sister?Do you have anything to say on the question?Would you please give me some paper to write on?My wish to visit Fra
27、nce 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）。(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）。(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）；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）。(4)不定式作定语时，一般可转换为定语从句，例to arrive=that will arrive。相关省略（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。
28、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
29、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
30、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
31、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。Weve missed the last bus.All we could do now is walk home.否定式Tell hi
32、m not to shut the windowShe pretended not to see me when I passed by. 我走过的时候，她假装没看见。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
33、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、Its for sb.和 Its 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：Its 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
34、形容词，如good,kind,nice,clever,foolish,right。Its 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tooto（1）tooto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
35、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”。Its 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。Im only too pleased to be able to help you. 我非常高兴能帮助你。He was but too ea
36、ger to get home. 他非常想回家。相互区别不定式与介词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
37、，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 solders had no choice but to give in.On Sunday afternoon I had nothing to do but watch TV.区别联系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：hate,like,love前有would(should)时，如：Id like
38、 to have a cup of coffee.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.begin,continue,start与know,understand等状态动词连用时，如：I soon began to understand what was happening.advise,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 dont per
39、mit our/us swimming in the lake.Our teachers dont 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。forget,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：Dont forget to post the letter for me.Have you forgotten meeting her in Beijing Airport?Remember to close the windows before you l
40、eave.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.语义不同目录1stop to do（停现在做的去做另一件事）stop doing（停止正在做某事）2 forget to do（忘记去做某事）forget doing（忘记做了某事）3remember to do（记得要去做某事）remember doing
41、（记得做过某事）4 regret to do（遗憾做某事）regret doing（遗憾做了某事）5cease to docease doing6 try to do（努力做某事）try doing（试着做某事）7go on to do（继续去做某事）go on doing（继续做某事）8 afraid to do（担心做某事）afraid doing（担心正在做的事）9interested to do（对做某事感兴趣）interested doing（对正在做的感兴趣）10 mean to do（打算做某事）mean doing（做某事很有意义）11 begin/ start to do（开
42、始去做某事）begin/ start doing（开始做某事）forget doing/to doforget 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.办公室的灯还在亮着，他忘记关了。(没有做关灯的动作)He forgot turning the light off.他忘记他已经关了灯了。( 已做过关灯的动作)Dont forget to come tomorrow.别忘了明天来。(to come动作未做)remember doing
43、/to doremember to do 记得去做某事(未做)remember doing记得做过某事(已做)Remember to go to the post office after school.记着放学后去趟邮局。Dont you remember seeing the man before?你不记得以前见过那个人吗？regret doing/to doregret to do对要做的事遗憾。(未做)regret doing对做过的事遗憾、后悔。(已做)I regret to have to do this,but I have no choice.我很遗憾必须这样去做，我实在没有办
44、法。I dont regret telling her what I thought.我不为告诉她我的想法而后悔。cease doing/to docease to do长时间，甚至永远停做某事。cease doing短时停止做某事，以后还会接着做。That department has ceased to exist forever.那个部门已不复存在。The girls ceased chatting for a moment when their teacher passed by.姑娘们在老师走过时，停了会聊天。try doing/to dotry to do努力，企图做某事。try
45、doing试验，试着做某事。You must try to be more careful.你可要多加小心。I tried gardening but didnt succeed.我试着种果木花卉，但未成功。go on doing/to dogo on to do做了一件事后，接着做另一件事。go on doing继续做原来做的事。After he had finished his maths，he went on to do his physics.做完数学后，他接着去做物理。Go on doing the other exercise after you have finished thi
46、s one.作完这个练习后，接着做其他的练习be afraid doing/to dobe afraid to do不敢，胆怯去做某事，是主观上的原因不去做，意为“怕”；be afraid of doing担心出现doing的状况、结果。doing 是客观上造成的，意为“生怕，恐怕”。She was afraid to step further in grass because she was afraid of being bitten by a snake.她生怕被蛇咬着，而不敢在草丛中再走一步。She was afraid to wake her husband.她不敢去叫醒她丈夫。Sh
47、e was afraid of waking her husband.她生怕吵醒她丈夫。.be interested doing/to dointerested to do对做某事感兴趣，想了解某事。interested in doing对某种想法感兴趣，doing 通常为想法。I shall be interested to know what happens.我很想知道发生了什么事。(想了解)Im interested in working in Switzerland. Do you have any idea about that我对在瑞士工作感兴趣。你想过这事吗?(一种想法)mean doing/to do
