動詞不定式用法

1、動詞不定式用法不定式是動詞的一種非限定式，它是不受主語的單復數(shù)、人稱、等的限定及影響的一種動詞形式，但有時態(tài)和語態(tài)的變化。一、動詞不定式的基本結(jié)構(gòu)動詞不定式的基本形式為：to+動詞原形，有時可不帶to。不定式的否定形式是： not to+動詞原形。在句中除不能作謂語外，其他成分都可作。如：主語、表語、 賓語、賓語補足語、定語和狀語等。注意：不定式之前的to （又稱為小品詞）與介詞to的功能不同。介詞to之后要 接名詞或代詞的賓格，或相當于名詞的短語作它的賓語；而不定式符號to的后面需要跟動詞原形。speak to him （to是介詞）對他講話to speak English （to是不定式的

2、小品詞）講英語二、動詞不定式的用法不定式在句中有各種作用，一般可歸類為三種基本用法：作名詞，作形容詞，作 副詞。（一）不定式作名詞的用法不定式起名詞作用，在句子中擔當主語、表語、賓語和賓語補足語。1.作主語名詞用法的不定式和名詞一樣，可擔任句子的主語。To grow more trees here is very importa nt.（=It is very important to grow more trees here.） 在這里多種些樹是非常重要的。To hear your voice is so ni ce.（=It is so nice to hear your voice.）聽

3、至 M爾的聲音真高興。To speak En glish well is not easy for me.（=It is not easy for me to speak En glish.）把英語說好對我來說并不容易。To walk to school takes me twenty mi nu tes.（=It takes me twenty minutes to walk to school.）步行到學校我要花 20 分鐘。注意：在It isto的句型中，it是形式主語，真正的主語是不定式；使用這種 結(jié)構(gòu)，可以避免句子的頭重腳輕。通常不定式被視為第三人稱單數(shù)，所以動詞用is 或 was。

4、It is bad for your eyes to read in the sun.在陽光下看書對你的眼睛有害。另外，不定式作主語的句子，同時有另外一個不定式作表語時，不能轉(zhuǎn)換成 “Its to的句型。To see is to believe.百聞不如一見。） 不能轉(zhuǎn)換為：It is to believe to see.2. 作表語不定式像名詞一樣，可以放在 be動詞后面，形成表語。My work is to clea n the room every day.我的工作是每天打掃這間屋子。 Her dream is to be a lawyer.她的夢想就是成為一名律師。What they

5、want is to do it at onee.他們所想的就是立刻著手做這件事。 附加：（1）動詞不定式往往放在系動詞 be（， become, sou nd, taste等系動詞后面 一般不接不定式）的后面作表語，表示將來的情況，說明主語的內(nèi)容。例如：My wish is to become a teacher.我的愿望是當一名教師。Your job today is to clea n the playgro und.你今天的工作是打掃操場。（2）如果系動詞后的動詞說明主語的性質(zhì)，特征，相當于形容詞。這時就要用 現(xiàn)在分詞作表語，而不用不定式。例如：He said that the sto

6、ry was in terest ing.他說這則故事很有趣 Nurse s resp on sibility is tak ing care of patie nts.3. 作賓語不定式作賓語用在及物動詞之后。常用的及物動詞有：want, wish, hope, like, beg in, start, help, agree, refuse, promise, lear n, forget, know, n eed, try 等。They began to read and write.他們開始讀和寫。She wan ted to get home earlier that day.她那天

7、想要早一些到家。 They refused to do so.他們拒絕那樣做。I hope to visit Paris some day.我希望有一天能參觀巴黎。注意：（1）在某些復合賓語中，常用“it代替不定式，而把不定式放到后面去。He found it very difficult to get to sleep.他發(fā)現(xiàn)很難入睡。She thi nks it importa nt to study En glish well.她認為把英語學好很重要。（2）在 tell, show, teach, find out, decide, learn, forget 等動詞之后，常用一個帶連

8、接代詞或副詞的不定式作賓語。He doesn t kncwhich one to choose.他不知道應該選哪一個。My mother used to teach me how to read and write. 過去我母親常教我如何讀書 寫字。No one could tell me where to get this kind of bike.沒人告訴我在哪里能找到這種 自行車。4. 做賓語補足語She asked me to speak more loudly.賓語賓補Jim told him not to cry.吉姆告訴他不要哭。She advised him to do so.

9、她勸他這么做。We all kn ow him to be a clever boy.我們都知道他是一個聰明的孩子。He reminded me to lock the door when I left.他提醒我離開時鎖上門。注意：(1)有一些表示感官的動詞，如 see, hear, watch, feel, notice和某些使役動 詞，如let, make, have等，其后跟不定式作賓語補足語時，不定式通常不帶to.He saw Li Pi ng come into the classroo m.他看見李平走近了教室。Don t forget tdet her leave earlier

10、.另 S忘了讓她早點走。It made me feel thirsty.這東西讓我感到口渴。但當這些動詞用于被動語態(tài)時，作主語補足語的不定式要帶to.例如：He was see n to come into the classroom.他被看見走進了教室。I was made to do a lot of homework yesterday.我昨天被要求做很多家庭作業(yè)。(2) 感官動詞后面還可用現(xiàn)在分詞作賓語。區(qū)別為：不定式表示動作發(fā)生了，側(cè) 重全過程；現(xiàn)在分詞則表示動作正在進行。如：I saw him come in.我看見他進來了。I saw him coming in.我看見他正往里走

11、。動詞help之后，帶to或不帶to都可以。Will you please help me (to) take this suitcase 請你幫我提一下這個衣箱好嗎 She ofte n helps her mother (to) clea n their house.她經(jīng)常幫助她媽媽打掃房子。(二) 不定式作形容詞的用法作定語1. 不定式有時起形容詞作用修飾名詞或代詞，在句中擔任定語。不定式作定語 時，它的位置在它所修飾的名詞或代詞之后。I have a lot of work to do.我有許多事情要做。Have you got anything to say 你還有什么要說的嗎 (s

12、ometh ing, any thi ng, nothing, everything等復合不定代詞常用不定式做后置定語。)She is the last to come.她是最后一個到的。(當名詞前有 the first ,the last, the only 等以及最高級時： eg: She is always the first to come and the last to leave.)eg: He spoke loudly (only to / in order to/so as to) be heard.比較： He rushed to the station only to fi

13、nd the train gone .(結(jié)果狀語)注意：(1)如果修飾不定代詞的還有形容詞時，它們的位置應該是：不定代詞+形容詞+不定式。I have someth ing importa nt to do. 我有些重要的事要做。Give me somethi ng hot to drink.給我一些熱的東西喝。(2)如果不定式是不及物動詞，或者不定式修飾的名詞或代詞是不定式動詞的地 點、工具等，不定式之后要加一個介詞。This is the best room for you to live in.這是最適合你住的房間。There is nothing to worry about. 沒什么

14、事情可擔心的。I want to borrow a piece of paper to write on. 我想借張紙寫字。(3) 不定式作定語時，一般可轉(zhuǎn)換為定語從句 The next train to arrive is from Shanghai. (to arrive=that will arrive ) 下一列到站的火車來自上海。附：不定式主動被動討論A) 不定式修飾的名詞或代詞和不定式構(gòu)成邏輯上的主謂關(guān)系時，不定式往往用主動形式.Have you got a key to uni ock the door (A key uniocks the door.)B) 不定式和它前面被修飾

15、的名詞或代詞構(gòu)成邏輯上的動賓關(guān)系，又和該 句主語構(gòu)成邏輯上的主謂關(guān)系時，不定式常用主動形式.I have got a letter to write . ( I write letter.)He needs a room to live in. ( He lives in a room )I know what to do . ( I do what.)但這句如改為下列形式，不定式就得用被動形式：I know what is to be done.這是因為 what is to be done是賓語從句，從句中的主語 what是動 詞do的動作對象C) 不定式作表語形容詞的狀語，和句中主語構(gòu)成

16、邏輯上的動賓關(guān)系時，不定式多用主動形式，這是因為人們往往認為形容詞后省去了for one或forpeople .例如：He is hard to talk to. ( to talk to him.)The book is difficult to un dersta nd. ( to un dersta nd the book.)但如果強調(diào)句中的受事者時，亦可用不定式被動式，例如：The handwriting is very difficult to be read.The box is too heavy to be lifted.D) 在“there十be”的結(jié)構(gòu)中，當說話人考慮的是必

17、須有人去完成某件事時，不定式用主動形式，如果說話人強調(diào)的是事情本身必須完成，則用被動形式.There is a lot of work to do. ( Somebody has to do the work )There is a lot of work to be done .( The work has to be don e.)請注意下面兩個句子的含義是不同的：There is nothi ng to do.意為無事可做，感到十分乏味.There is n othi ng to be done .意為某東西壞了，無法使之恢復正常.(三) 不定式作副詞的用法不定式可起副詞的作用，在句中表

18、目的、結(jié)果、原因等。1.表目的He came to teach the little girl En glish.他來給這個小女孩上英語課。I we nt to visit my uncle last Sun day.上星期天我去拜訪了我的叔叔。In order to study English well, she often does more speaking and writing.為了把英語學好，她經(jīng)常多說多寫。2.表結(jié)果What has he said to make you so sad他說了什么話讓你這樣傷心They lifted a rock only to drop in o

19、n their own feet.他們搬起石頭砸了自己的腳。3.表原因I am sorry to hear that.聽到這件事，我感到很難過。The questi on is quite difficult to an swer. 這個問題很難回答。三、動詞不定式的幾個重要結(jié)構(gòu)1. 不定式的否定結(jié)構(gòu)：n ot +to doHe told me not to be late.他告訴我別遲到。She asked the old man not to be an gry.她請這位老人別生氣。注意：不定式否定句不同于否定句形式。不定式否定句沒有助動詞，否定句有助 動詞。I didn t ask hi

20、m to come he我沒請他來。I asked him not to come here.我請他不要來。2. 不定式的復合結(jié)構(gòu)：fo葉名詞（代詞）+ 不定式It is very difficult for me to do this job.對我來說做這件工作很困難。It is very important for you to practise your oral English in the daily life.在日常生活中練習你的英語口語是非常重要的。3. 不定式的“of名 （代）+不定式”結(jié)構(gòu)It is very nice of you to help me.你來幫我真是太好了。

21、It s kiodyou to think so much of us.難為你這樣替我們想。It was careless of him to lose so many thi ngs.他丟了這么多東西，真是太粗心 了。4. 不定式的 疑問詞+ 不定式”結(jié)構(gòu)此結(jié)構(gòu)在句中的語法作用有以下幾點：作主語How to use the computer is a problem.如何使用計算機是個問題。作表語The questi on is how to go to the park .問題是如何去公園。作賓語I didn t deoideere to go.我還沒有決定去哪兒。注意：帶特殊疑問句的不定

22、式可跟帶特殊疑問詞的賓語從句進行句型轉(zhuǎn)換。He didn t knowhat to do. =He didn t kwhat he should do.他不知道要做什么。（4）作賓語補足語She ofte n teaches me how to read and write.她常教我如何讀書寫字。（5）作同位語The problem of which to select as his successor was quickly disposed of.5. 不定式的“too形容詞或副詞+to do sth.和”“too形容詞或副詞+for sb/ sth +to do sth.結(jié)構(gòu)。She i

23、s too young to go to school.她太小不能上學。This pair of trousers is too dirty for him to wear.這條褲子太臟了，他不會穿他的。too結(jié)構(gòu)和too - for結(jié)構(gòu)連接句子的區(qū)別：tootc結(jié)構(gòu)連接兩個單句中主語相同的句子。He is too tired. He can t go any further.He istoo tired to go any further.他太累了，再也走不動了。too -for結(jié)構(gòu)連接兩個單句中主語不相同的句子。The box is very heavy. She couldn t car

24、ry it.Thebox is too heavy for her to carry.這個箱子太重了，她搬不動。(2)這兩種句型還可用sothat 如此以至于)結(jié)構(gòu)來連接，構(gòu)成狀語從句.He is so tired that he can t go any further.t carry it.The box is so heavy thatne could n6.不定式的“(not)形容詞或副詞+enough to結(jié)構(gòu)和 “(not)形容詞或副詞+eno ugh for sb/ sth to do. ”這種結(jié)構(gòu)中不定式也用來作狀語表結(jié)果.意思是“能夠做某事”或“不能做某 事”。He is o

25、ld eno ugh to join the army.他至 U參軍的年齡了。The little boy doesn t studyWeigtesiough to understand you.這個小男孩英語學得不好，他不懂你的意思。這種結(jié)構(gòu)可跟“tooto結(jié)構(gòu)進行句型互換。This question was too difficult for everybody in our class to answer.這個問題太難了，我們班的所有人都回答不上來。This questi on was not easy eno ugh for everybody in our class to an s

26、wer.這個問題不太容易，我們班的所有人都回答不上來。四、省略動詞不定式符號to的幾種情況1. had better / Why not / Will you please / Shall w等句型后接動詞原 形。2. 感官動詞see/ hear/ watch/ notice等和使役動詞 make/ have/ let等后接動詞原 形做賓補。3. help后接動詞不定式作賓補時的to可省也可不省。4. would rather后接動詞原形。如：I would rather stay at home tha n go for a walk.我寧愿呆在家里而不愿去散步。注意：為了避免重復，動詞不定

27、式中與上文相同部分可以省略掉，但to須保持下來。(1) Will you join me in a walk你愿意和我一塊兒去散步嗎I e bglad to.我愿意。-Did you find the refere nee books about it 你找到有關(guān)的參考書了嗎-No, I tried to, but failed.沒有。我盡力了，但沒找到。不定式的時態(tài)、語態(tài) 不定式都表發(fā)生在過去或現(xiàn)在的將來、目的或結(jié)果，有各種時態(tài)和語態(tài) 一般式 to do /to be done完成式 to have done /to have been done進行式 to be doing 完成進行式 t

28、o have been doing（根據(jù)語境來判斷該用何種時態(tài)和語態(tài)）（一）一般式表示動作通常與句子謂語所表示的動作或狀態(tài)幾乎同時發(fā)生， 或是 在它之后發(fā)生。I am glad to see you. 不定式動作與句子的謂語動詞同時進行。一般式被動 It s an honour for me to be invited.（與句子謂語同時發(fā)生）（這里為什么不用to invite,因為to invite不是修飾me的，不是定 語，而是真正主語）（二）不定式的正在進行時，表前一個動作發(fā)生時，不定式所表動作正在發(fā)生Some dogs were found to be looking for food around. 一些狗被發(fā)現(xiàn)正在四處尋找 食物。（三）不定式的完成式 1）發(fā)生在謂語動詞的動作或狀態(tài)前，常接不定式完成式的動詞有appear to have doneseem to have donehappen to（碰巧 have donebe said to have done,be reported to have donebe believed to have done