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、時態(tài)、語態(tài)等的限定及影響的一種動詞形式。一、動詞不定式的基本結構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 是不定式的小品詞) 講英

2、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。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 important.(=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 nice.(=It is so nice to hear your voice.) 聽到你的聲音真高興。

3、To speak English well is not easy for me.(=It is not easy for me to speak English.) 把英語說好對我來說并不容易。To walk to school takes me twenty minutes.(=It takes me twenty minutes to walk to school.) 步行到學校我要花20分鐘。注意：在It is to”的句型中，it是形式主語，真正的主語是不定式；使用這種結構，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。It is bad for yo

4、ur 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 “It is 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 clean 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 want is to d

5、o it at once. 他們所想的就是立刻著手做這件事。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, begin, start, help, agree, refuse, promise, learn, forget, know, need, try等。They began to read and write. 他們開始讀和寫。She wanted to get home earlier that day. 她那天想要早一些到家。They refused to do so. 他們拒絕那樣做。I hope to visit Par

6、is 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 thinks it important to study English 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，常用一個帶連接代詞或副詞的不定式作賓語。He doesnt know which one to choose. 他不知道應該選

7、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. 她勸他這么做。We all know him to be a clever boy. 我們都知道他是一個

8、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 Ping come into the classroom. 他看見李平走近了教室。Dont forget to let her leave earlier. 別忘了讓她早點走。It made me feel thirsty. 這東西讓我感到口渴。但當這些動詞

9、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 seen 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。(3) 動詞help之后，帶to或不帶to都可以。Will you please help me

10、 (to) take this suitcase? 請你幫我提一下這個衣箱好嗎？She often helps her mother (to) clean 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？She is the last to come. 她是最后一個到的。注意：(1) 如果修飾不定

11、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 something important to do. 我有些重要的事要做。Give me something 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. 沒什么事情可擔心的。I want to borrow a piece of pap

12、er 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。（三）不定式作副詞的用法不定式可起副詞的作用，在句中表目的、結果、原因等。1. 表目的He came to teach the little girl English. 他來給這個小女孩上英語課。I went to visit my uncle last Sunday. 上星期天我去拜訪了我的叔叔。In order to study E

13、nglish 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 on 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 question is quite difficult to answer. 這個問題很難回答。三、動詞不定式的幾個重

14、要結構1. 不定式的否定結構：not +to doHe told me not to be late. 他告訴我別遲到。She asked the old man not to be angry. 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 didnt ask him to come here. 我沒請他來。I asked him not to come here. 我請他不要來。2. 不定式的復合結構：for+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

15、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”結構It is very nice of you to help me. 你來幫我真是太好了。Its kind of you to think so much of us. 難為你這樣替我們想。It was careless of him to lose so many things. 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”結構

16、此結構在句中的語法作用有以下幾點：(1) 作主語How to use the computer is a problem. 如何使用計算機是個問題。(2) 作表語The question is how to go to the park. 問題是如何去公園。(3) 作賓語I didnt decide where to go. 我還沒有決定去哪兒。注意：帶特殊疑問句的不定式可跟帶特殊疑問詞的賓語從句進行句型轉(zhuǎn)換。He didnt know what to do. =He didnt know what he should do.他不知道要做什么。(4) 作賓語補足語She often teach

17、es me how to read and write. 她常教我如何讀書寫字。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.”結構。She is 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。(1) tooto結構和tooforto結構連接句子的區(qū)別：tooto結構連接兩個單句中主語相同的句子。He is too tired. He cant go

18、any further.He is too tired to go any further. 他太累了，再也走不動了。tooforto結構連接兩個單句中主語不相同的句子。The box is very heavy. She couldnt carry it.The box 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)結構來連接,構成狀語從句.He is so tired that he cant go any further.The box is so heavy that he couldnt ca

19、rry it.6. 不定式的 “(not)+形容詞或副詞+enough to”結構和 “(not)+形容詞或副詞+enough for sb/ sth to do.”這種結構中不定式也用來作狀語表結果.意思是“能夠做某事”或“不能做某事”。He is old enough to join the army. 他到參軍的年齡了。The little boy doesnt study English well enough to understand you.這個小男孩英語學得不好，他不懂你的意思。這種結構可跟 “tooto”結構進行句型互換。This question was too diffi

20、cult 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 question was not easy enough for everybody in our class to answer.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 we? / Let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 than 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？Ill be glad to. 我愿意。(2) Did you find the reference books about it? 你找到有關的參考書了嗎？ -No, I tr