1、动词不定式不定式定义：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。 “动词不定式”由动词+不定式构成。动词不定式在句中可以作句子除谓语之外的任何句子成分。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。然而在一些语言里（例如葡萄牙语） ，存在着受时态、人称和数量影响的不定式形态。亦有些语言完全没有不定式，例如阿拉伯语、保加利亚语和现代希腊语。1 时态语态1.1 介绍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
2、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：1.2 (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：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
3、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 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 do now.) There is nothing
4、 to be done now.(We can do nothing now.)1.3 (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 Ill 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。Im sorry to have given you so much trouble.He seems to have caught a cold.3) 进行时：表示动作正
5、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.一般在情绪后加 to do to do 也表将来2 一般结构疑问词 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：When to leave for London has not been decided yet. （不定式在句子中做主语）Mr. Smith
6、 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,discover,explain,find ou
7、t,forget,hear,know,lea rn,observe,understand,wonder 等。3 语法功能3.1 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：It+be+ 名词+to doIts our duty to take good care of the old.It takes sb+some time+to doHow long did it
8、take you to finish the work?It+be+ 形容词+for sb+to doIt is difficult for us to finish writing the composition in a quarter of an hour.It+be+ 形容词+of sb+to doIt is stupid of you to write down everything (that) the teacher says.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
9、容词，如：difficult,easy,hard,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 helpme with my English.(3)举例（1） Its ea
10、sy (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.当你不用车的
11、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）
12、 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. 眼见为实。(错)It is to believe to see.3.2 二、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） ，cond
13、escend（屈尊） ，consent（准许） ，decide（决定） ， demand（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） ，s
14、wear（发誓） ，tend（往往会） ，threaten（预示） ，undertake （承诺） ，volunteer （自愿做） ，vow（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,wond
15、er,hear,find out,explain,tellPlease 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 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
16、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.I find it difficult to learn English well.3.3 三、作补语1) 动词+宾语+不定式(to do)advise allow believe cause challenge compel declare encourage forbid force find hire induce
17、 instruct invite like order permit persuade remind request require select send 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。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 foun
18、d 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, consid
19、er, think, declare(声称), discover, fancy(设想), feel, find, guess, judge, imagine, know, prove, see(理解), show, suppose, take(以为), understandWe 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. inve
20、nting C. to have invented D. having invented 答案：A. 由 consider to do sth. 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, meanThe book i
21、s 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,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 h
22、im 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
23、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 him try again.- He is let try again.(let 的主补与宾补均用秃头不定式 )3.4 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。To be kind to the enemy is to be cruel to the people.My chief purpose is to point out the difficulties of the matter.
24、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.What he likes is taking a walk after supper.The story told by Mr.Wang is interesting.句动
25、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。3.5 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
26、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. 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3.6 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。
27、3.7 六、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 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
28、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。4 相关形式4.1 省 to 的动词不定式介绍（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。ought to 没有人称和数的变化，后接动词原形可以
29、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 work the whole ni
30、ght.=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
31、。（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.（1
32、1）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。Weve missed the last bus.All we could do now is
33、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 doesnt 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
34、词不定式，当其用于被动时， to 不可省略。4.2 否定形式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 shutD. 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.
35、 A. not to see B. not seeing C. to not seeD. 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 nev
36、er.（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. e
37、ating 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。5 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 y
38、ou 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、 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
39、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。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）too to 太以至于 He is too excited to speak.他太激动了
40、，说不出话来。Can I help you 需要我帮忙吗Well,Im 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 a
41、ble 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。6 to 的用法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 attenti
42、on to 注意介词 but,except,besides+to dodo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.7 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
43、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 to have a cup of coffee.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.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,enco
44、urage,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 permit 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 meeti
45、ng 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.8 语义不同8.1 目录1 stop to do stop doing 2 forget to do forget doi
46、ng3 remember to do remember doing 4 regret to do regret doing5 cease to do cease doing 6 try to do try doing7 go on to do go on doing 8 afraid to do afraid doing9 interested to do interested doing 10 mean to do mean doing11 begin/ start to do begin/ start doing8.2 1 forget doing/to doforget to do 忘记
47、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)典型例题 The light in the office is still on. Oh，I forgot_. A. turning it
48、off B. turn it off C. to turn it off D. having turnedit off答案：C。由 the light is still on 可知灯亮着，即关灯的动作没有发生，因此用 forget to do sth.而 forget doing sth 表示灯已经关上了，而自己忘记了这一事实。此处不符合题意。8.3 2 stop doing/to dostop to do 停止，中断做某事后去做另一件事。stop doing 停止做某事。They stop to smoke a cigarette. 他们停下来，抽了根烟。I must stop smokin
49、g. 我必须戒烟了。典型例题 She reached the top of the hill and stopped _ on a big rock by theside of the path. A. to have rested B. resting C. to rest D. rest答案：C。由题意可知，她到了山顶，停下来在一个路边的大石头上休息。因此，应选择“stop to do sth.停下来去做另一件事” 。而不仅仅是爬山动作的终止，所以 stop doing sth.不正确。8.4 3 remember doing/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
