動詞不定式講解

1、動詞不定式的用法概念：動詞不定式由to+動詞原形構(gòu)成。這里的to是不定式標(biāo)志，沒有詞義。不定式具有 名詞、 形容詞或副詞 的某些語法功能，又有動詞的時態(tài)和語態(tài)的特點及作用。 可以做主語、賓語、 賓語補(bǔ)足語、表語、定語、狀語。一、作主語動詞不定式作主語時，句子的謂語動詞常用單數(shù)，其位置有以下兩種：（1）把不定式置于句首。如：To get there by bike will take us half an hour.（2）用 it 作形式主語，把真正的主語不定式置于句后，常用于下列句式中。如： It + be +名詞 + to doIt's our duty to take good c

2、are of the old. It takes sb+some time+to doHow long did it take you to finish the work? It + be +形容詞 + for sb + to doIt is difficult for us to finish writing the composition in a quarter of an hour.在句型中，常用表示客觀情況的形容詞，如：easy, difficult, hard, important, possible, impossible, comfortable, necessary, be

3、tter;the first, the next, the last, the best, too much, too little, not enough It+be+形容詞 + of sb+to doIt is stupid of you to write down everything the teacher says.在句型中,常用 careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise rude, clever, foolish, thoughtful, thoughtless （ 欠考慮的

4、；不考慮的） , brave,considerate（考慮周到的），sefish（自私的）等表示贊揚(yáng)或批評的詞。在不定式前的sb,可看作其邏輯主語。這一句式有時相當(dāng)于 Sb is+形容詞+ to do句式，如：It's kind of you to help me with my English.=You are kind to help me with my English. It seems（appears） +形容詞 + to doIt seemed impossible to save money.It seemed selfish of him not to give the

5、m anything. 他不給他們?nèi)魏螙|西，這顯得太自私 了。注意 ： 1） 其他系動詞如， look ， appear 等也可用于此句型2） 不定式作為句子主語時，動詞用單數(shù)形式。3）當(dāng)不定式作主語的句子中又有一個不定式作表語時，不能用 It isto的句型 對應(yīng)性： To see is to believe. 百聞不如一見。二、作賓語1） 以下動詞后，只能跟不定式作賓語afford（付得起）,agree （同意）,aim（力求做至Q, appear （顯得）,arrange （安排）,ask（要求）,attempt （試圖）,care （想要）,choose （決定）,claim （聲稱）

6、,condescend （屈 尊）,consent （準(zhǔn)許）,decide （決定）,demand （要求）,determine （決心）,endeavor （竭 力），expect （期待），fail （未履行），help （幫助），hesitate （猶豫），hope （希望），learn（學(xué)會）,manage （設(shè)法）,neglect （疏忽）,offer （主動提出）,plan （計戈U） , prepare （準(zhǔn) 備），pretend （假裝）,proceed （接著做），promise （答應(yīng)），prove （證明），refuse （拒絕）， resolve （解決），seem（覺

7、得好像）,swear （發(fā)誓）,tend （往往會）,threaten （威脅）,undertake（承諾）,volunteer （自愿做），vow （發(fā)誓）,want （想要）,wish （希望） 舉例：The driver failed to see the other car in time.司機(jī)沒能及時看見另一輛車。I happen to know the answer to your question.我碰巧知道你那道問題的答案。2）動詞+疑問詞+不定式decide, know, consider forget, learn, remember, show, understand,

8、see, wonder, hear, find out, explain, tellPlease show us how to do that.請演示給我們?nèi)绾稳プ?。There are so many kinds of tape-recorders on sale that I can't make up my mind which tobuy.有這么多的錄音機(jī)，我都拿不定主意買哪一種。注意:疑問詞帶不定式在句中作主語時，謂語動詞用單數(shù)。The question is how to put it into practice.問題是怎樣把它付諸實施。3）當(dāng)復(fù)合賓語中的賓語是不定式時，先用

9、形式賓語it代替不定式，把不定式置于補(bǔ)語之后， 即：主語+動 詞+it +補(bǔ)語+to do句式。如：We think it quite important for us to learn a foreign language well.He feels it his duty to help the poor.I find it difficult to learn English well.三、作補(bǔ)語1）動詞+賓語+不定式（to do）advise allow believe cause challenge compel （強(qiáng)迫,使不得不）declareencourage forbid fo

10、rce findhire induce （弓 I誘，勸導(dǎo)）instruct （命令， 指示）invitelike order permit persuade remind request require select send suppose tell train urge （催促，鼓勵）例句：a. Father will not allow us to play on the street.父親不讓我們在街上玩耍。b. We believe him to be guilty.我們相信他是有罪的。find的特殊用法：find后可用分詞做賓補(bǔ)，或先加形式賓語，再加形容詞，最后加帶to的動詞不定式

11、。find 后也可帶一個從句。此類動詞還有g(shù)et, have。I found him lying on the ground.I found it important to learn.I found that to learn English is important.典型例題：The next morning she found the man in bed , dead.A. lying B. lie C. lay D. laying答案：A. find的賓語后面，用分詞或分詞短語，起賓語補(bǔ)足語作用?，F(xiàn)在分詞表達(dá)主動， 也表達(dá)正在進(jìn)行，過去分詞表達(dá)被動。lie:躺 過去式lay,過去分詞

12、lain ,現(xiàn)在分詞lying;lie:說謊 過去式lied,過去分詞lied ,現(xiàn)在分詞lying;lay:安放過去式laid,過去分詞laid,現(xiàn)在分詞laying;2） to + be的不定式結(jié)構(gòu)，作補(bǔ)語的動詞。Acknowledge _ 承認(rèn)，供認(rèn)， believe, consider, think, declare（聲稱），discover, fancy（設(shè)想），feel, find, guess, judge, imagine, know, prove, see陛解）,show,suppose, take（ 以為 ）, understandWe consider Tom to be

13、 one of the best students in our class.我們認(rèn)為湯姆是班上最好的學(xué)生之一。3） to be +形容詞Seem, appear, be said, be supposed, be believed, be thought,be known, bereported,hope, wish, desire, want, plan, expect, mean The book is believed to be uninteresting. It is believed that 人們認(rèn)為這本書沒什么意思。有些動詞需用 as 短語做補(bǔ)語，如 regard, thin

14、k believe, take, consider.We regard Tom as our best teacher. 我們認(rèn)為湯姆是我們最好的老師。Mary took him as her father . 瑪麗把他當(dāng)作自己的父親。四、作表語不定式作表語表示具體動作或?qū)韯幼?；動名詞作表語表示抽象的一般行為。 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. What I would suggest is

15、 to put off the meeting.當(dāng)主語和表語都是不定式時，其含義一是條件，一是結(jié)果（例）。當(dāng)主語是aim,duty,hope,idea,mista ke,plan,purpose,suggestion 等為中心詞的名詞詞組（例）時，或 以what引導(dǎo)的名詞性分句（例），不定 式說明主語的內(nèi)容。 Our work is serving the people. What he likes is taking a walk after supper. The story told by Mr Wang is interesting.旬動名詞作表語，與主語部分可以轉(zhuǎn)換，如 Servin

16、g the people is our work,而句中是現(xiàn)在分詞作 表語，說明主語的性質(zhì)、狀態(tài)，現(xiàn)在分詞具有形容詞的各種特征，另外，動名詞作表語還應(yīng)與進(jìn)行時態(tài)區(qū)別開來。五、作狀語1）目的狀語Toonly to （僅僅為了）， in order to, so as to, so（such）as to 如此以便）He ran so fast as to catch the first bus. 他飛快地跑以便趕上第一班車。I come here only to say good-bye to you. 我來僅僅是向你告別。2）作結(jié)果狀語，表事先沒有預(yù)料到的，要放在句子后面。He searched

17、 the room only to find nothing.3） 表原因I'm glad to see you.典型例題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. 如果不定式為不及物動詞，其后應(yīng)有必要的介詞。當(dāng)動詞與介詞連用時，常位于 "形容詞+動詞不定式"結(jié)構(gòu)的末尾。The water is too cold to drink.（ 不用被動 ）六、作定語1 .不定式作定語不定式

18、在句中作定語，置于被修飾的名詞或代詞之后。如：1) The next train to arrive is from Washington.2) Do you have anything to be taken ( to take)to your sister?3) Do you have anything to say on the question?4) Would you please give me some paper to write on?5) My wish to visit France has come true at last.不定式短語作定語和被修飾詞之間表示以下關(guān)系：

19、(1)表示將來的動作(例)。(2)與被修飾詞之間有動賓關(guān)系，如是不及物動詞，則需加介詞(例)。(3)與被修飾詞之間有動賓關(guān)系，同時與句中其它詞之間又有邏輯上的主謂關(guān)系時，盡管有被動含義，卻仍 用主動語態(tài)(例)；如只有動賓關(guān)系，而無邏輯上的主謂關(guān)系，則需用被 動語態(tài)(例)。(4)不定式作定語時，一般可轉(zhuǎn)換為定語從句，例 to arrive=that will arrive 。七省 to 的動詞不定式介紹6) 情態(tài)動詞 ( 除 ought 外， ought to 意思是 "應(yīng)該 " ，是情態(tài)動詞，只有一種形式，后邊接動詞不定式，to不能省略。ought to沒有人稱和數(shù)的變化，

20、后接動詞原形可以表示現(xiàn)在、將來或過去將來，由時間狀語或上下文決定。例如：They ought to come tomorrow. 他們明天應(yīng)當(dāng)來) ：7) 使役動詞let, have, make ：8) 感官動詞see, watch, look at, notice , observe, hear, listen to, smell, feel, find 等后作賓補(bǔ)，省略 to 。注意：在被動語態(tài)中則 to 不能省掉 。在使役動詞中 get 除外 (get sb. to do sth.)I saw him dance.=He was seen to dance.The boss made t

21、hem work the whole night.=They were made to work the whole night.9) 表示個人意愿或傾向的 would rather ， had better ， might(just) as well ： rather than 置 于句首時。Rather than ride on a crowded bus, he always prefers to ride a bike.10) Why/ why not11) help 可帶 to ，也可不帶 to, help sb (to) do sth ：12) but 和 except： but

22、前是動詞 do 時，后面出現(xiàn)的動詞用不帶to 的動詞不定式。13) 由 and, or 和 than 連接的兩個不定式，第二個to 可以省去：14) 通常在 discover, imagine, suppose, think, understand 等詞后，可以省去to be ：He is supposed (to be) nice. 他應(yīng)該是個好人。15) but 作介詞，后接不定式結(jié)構(gòu)時，前面謂語動詞部分若含有 do 的形式時， but 后的不定式要省去to ，否則要帶to 。He wants to do nothing but go out.He wants to believe any

23、thing but to take the medicine.11)當(dāng)兩個或多個不定式短語由連詞 and ， but 或 or 連接時，后一個或幾個不定式符號to常省略。但若表示對比、對照關(guān)系時，則不能省略。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)不定式做表語時，一般要帶to,但若主語部分中含有do的各種形式時，符號to可省 去。We've missed t

24、he last bus.All we could do now is walk home.典型例題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 后面接不帶to 的不定式，因此選 D 。2) Paul doesn't have to be made _. He always works hard.A. learn B. to learn C. learned D

25、. learning答案： B. make 后接不帶 to 的動詞不定式，當(dāng)其用于被動時， to 不可省略。13，在口語中,為避免重復(fù),常用 "to" 代替不定式結(jié)構(gòu),有時甚至可以把to 省略 .如 :-Did you go to visit the Great Wall-No, I wanted to, but there wasn't enough time.動詞不定式的否定式.not to do.Tell him not to shut the window She pretended not to see me when I passed by. 我走過的時

26、候，她假裝沒看見。典型例題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 的否定形式為 tell sb not to do sth.2) She pretended _ me when I passed by.A. not to see B. not seeing C. to not seeD. having not seen答案： A。 pretend 后應(yīng)接不定式。其否定形式為 pretend not to do sth. 。3) M

27、rs. Smith warned her daughter _ after drinking.A. never to drive B. to never driverC. never driving D. never drive答案：A 。 warn sb to do sth. 的否定形式為 warn sb not to do sth. 此處用的是否定詞 never.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 itD

28、. do not to答案：A。 not to 為 not to do it 的省略形式?？梢灾挥?to 這個詞，而不必重復(fù)整個不定式詞組。及物動詞do 后應(yīng)有名詞、代詞等，否則不對，因此B ， D 不對。5) The patient was warned _ oily food after the operation.A. to eat no B. eating not C. not to eatD. not eating答案： C。 warn 一詞要求后用不定式， 此處為不定式的被動， 否定形式為 be warned not to do。八、不定式的特殊句型不定式的特殊句型so as to

29、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.湯姆對事故保持沉默是為了不丟掉他的工作。Go in quietly so as not to wake the baby.輕點進(jìn)去，別驚醒了嬰兒。2) so kind as to -勞駕Would you be so kind as to tell me the time?勞駕，現(xiàn)在幾點了。3) "Why not + 動詞原形 " 表達(dá)向某人提出建議"為什么不 ？""

30、干嗎不？”例如：Why not take a holiday?干嗎不去度假?4) It's for sb. 和 It's of sb.1) for sb. 常用于表示事物的特征特點，表示客觀形式的形容詞，如 easy, hard, difficult, interesting, impossible 等：It's very hard for him to study two languages. 對他來說學(xué)兩門外語是很難的。2) of sb 的句型一般用表示人物的性格， 品德， 表示主觀感情或態(tài)度的形容詞， 如 good, kind, nice, clever, foo

31、lish, right 。It's very nice of you to help me. 你來幫助我，你真是太好了。for 與 of 的辨別方法：用介詞后面的代詞作主語， 用介詞前邊的形容詞作表語， 造個句子。 如果道理上通順用 of ，不通則用 for 。如：You are nice. (通順，所以應(yīng)用of) 。He is hard. (人是困難的，不通，因此應(yīng)用 for 。 )4、不定式的特殊句型too - to1) too - to 太以至于 He is too excited to speak.他太激動了，說不出話來。Can I help you ? 需要我?guī)兔?Well

32、, I'm afraid the box is too heavy for you to carry it, but thank you all the same. 不 用了。這箱子太重，恐怕你搬不動。謝謝您。2) 如在 too 前有否定詞，則整個句子用否定詞表達(dá)肯定， too 后那個詞表達(dá)一種委婉含義，意 為" 不太 " 。It's never too late to mend. (諺語 )改過不嫌晚。3)當(dāng)too前面有only, all, but時，意思是：非常 等于very。I'm only too pleased to be able to

33、help you. 我非常高興能幫助你。He was but too eager to get home. 他非常想回家。動詞不定式的"to" 與介詞的 "to" 區(qū)別 to 有兩種用法：一為不定式+動詞原形；一為介詞+名詞 /動名詞 , to 在下面的用法中是介詞，即 to+ 名詞 /動名詞：admit to 承認(rèn)，confess to承認(rèn)，be accustomed to 習(xí)慣于，be used to 習(xí)慣于， stick to 堅 持， turn to 開始， 著手于， devote oneself to 獻(xiàn)身于， be devoted to 致力

34、于， look forward to 盼望， pay attention to 注意 ， contribute to, object to介詞 but,except,besides+to do(do)在這種句型中， 如介詞前有動詞 do ， 后面應(yīng)接不帶 to 的不定式； 如無 do ， 則接 to 不定式，即帶 do 不帶 to, 帶to 不帶 do。如：The enemy soldiers had no choice but to give in.On Sunday afternoon I had nothing to do but watch TV .九、動詞不定式與動名詞區(qū)別與聯(lián)系1動

35、名詞與不定式的區(qū)別：動名詞表達(dá)的是：狀態(tài)，性質(zhì)，心境，抽象，經(jīng)常性，已發(fā)生的不定式表達(dá)的是：目的，結(jié)果，原因，具體，一次性，將發(fā)生的2接不定式或動名詞，意義相同3）在下列情況下，一般要用不定式：hate,like,love 前有 would（should）時，如：I'd like to have a cup of coffee.當(dāng)謂語動詞begin,continue,start等是進(jìn)行式時，如：The students are starting to work on the difficult maths problem.begin,continue,start 與 know,unde

36、rstand 等狀態(tài)動詞連用時，如： I soon began to understand what was happening.4. advise,allow,encourage,forbid,permit等動詞后接動名詞作賓語，或帶不定式作賓語補(bǔ)足 語。如：Our teachers don't permit our/us swimming in the lake.Our teachers don't permit us to swim in the lake.4）部分動詞后接不定式或動名詞時，意義差別較大，應(yīng)根據(jù)句子語境選擇使用。forget,remember,regret

37、后接不定式，表示現(xiàn)在或未來的動作，接動名詞表示動作已經(jīng)發(fā) 生。如：Don't forget to post the letter for me.Have you forgotten meeting 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 regr

38、etted ordering these books from abroad.動名詞與不定式語義不同的有11組1 stop to do/ stop doing2 forget to do /forget doing3 remember to do /remember doing4 regret to do /regret doing5 cease to do長時間，甚至永遠(yuǎn)停止）/ cease doing （短時間）6 try to do （盡力）、 try doing （嘗試）7 go on to do go on doing8 afraid to do 不敢去做某事afraid of do

39、ing 一向害怕做某事，表示習(xí)慣9 interested to do對某事感興趣，想了解、 interested doing對某種想法感興趣10 mean to do 打算、mean doing 意味11 begin/ start to do begin/ start doing十，動詞不定式的時態(tài)，語態(tài)時態(tài)一般式：動詞不定式一般式表示的動作發(fā)生在謂語動詞之后，有時表示同時發(fā)生.如：I hope to become a university student this year.（to become 發(fā)生在 hope 之后）We often hear Dick play the piano in

40、 the next room.（play 和 hear 同時發(fā)生）完成式：表示的動作發(fā)生在謂語動詞所表示的動作之前.如：I'm sorry to have kept you waiting.We are too young to have seen the old society.進(jìn)行式：表示的動作與謂語動詞同時發(fā)生.如：The teacher happened to be correcting our papers when I came in.They seemed to be discussing something important.（2）語態(tài)如果動詞不定式的邏輯主語是這個不定式所表示的動作的承受者,不定式一般要用被動語態(tài)形式.如:It's a great honour to be invited to Mary's birthday party.（ 不定式作主語）It was impossible for lost time to be made up.（ 不定式作主語）I wish to be sent to work in the country