整理版动词不定式用法

1、动词不定式用法一、动词不定式的基本结构动词不定式的基本形式为:to+动词原形,有时可不带to。I decided to buy a bike.-I decided not to buy a bike.=I didnt decide to buy a bike.不定式的否定形式是:not to+动词原形。在句中除不能作谓语外,其他成分都可作。如:主语、表语、宾语、宾语补足语、定语和状语等。它是不受主语的单复数、人称、时态、语态等的限定及影响的一种动词形式。注意:不定式符号to的后面需要跟动词原形。二、动词不定式的用法不定式在句中一般可归类为三种基本用法:作名词,作形容词,作副词。(一 不定式作名

2、词的用法-在句子中担当主语、表语、宾语和宾语补足语。作主语To learn English well is very important.注意:英语中为了避免头重脚轻,常用it代替to do sth不定式做形式主语,然后将真正的主语to不定式放在句尾。*通常不定式被视为第三人称单数,所以谓语动词用is或was。=It is very important to learn English well.To speak English well is not easy for me.(=_. 把英语说好对我来说并不容易。不定式作主语的句子,且另一个不定式作表语时,不转换成“It is to”To s

3、ee is to believe. (百闻不如一见。不能转换为:It is to believe to see.2.作表语-可以放在系动词后面,形成表语。(主语表语位置互换依然成立 My work is to clean the room every day. 我的工作是每天打扫这间屋子。Her dream is to be a lawyer. 她的梦想就是成为一名律师。3.作宾语不定式作宾语用在及物动词之后。常用的及物动词有:want, wish, hope, like, begin, start, help, agree, refuse, promise, learn, forget, k

4、now, need, try等。They began to read and write. 他们开始读和写。They refused to do so. 他们拒绝那样做。注意:(1 在某些复合宾语中,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. 他发现很难入睡。She thinks it important to study English well. 她认为把英语学好很重要。4.做宾语补足语She asked me to speak more loudly.宾语宾补Jim told him not to

5、cry. 吉姆告诉他不要哭。We all know him to be a clever boy. 我们都知道他是一个聪明的孩子。注意:(1 有一些表示感官的动词,如see, hear, watch, feel, notice和某些使役动词,如let, make, have等,其后跟不定式作宾语补足语时,不定式通常不带to.He saw Li Ping come into the classroom. 他看见李平走近了教室。It made me feel unhappy.但当这些动词用于被动语态时,作主语补足语的不定式要带to. 例如:He was seen to come into the

6、classroom. 他被看见走进了教室。I was made to do a lot of homework yesterday. 我昨天被要求做很多家庭作业。(2 感官动词后面还可用现在分词作宾语。区别为:不定式表示动作发生了,侧重全过程;现在分词则表示动作正在进行。如:(3 动词help之后,带to或不带to都可以。Will you please help me (to take this suitcase? 请你帮我提一下这个衣箱好吗? She often helps her mother (to clean their house. 她经常帮助她妈妈打扫房子。(二不定式作形容词的用法

7、作定语1. 不定式有时起形容词作用修饰名词或代词,在句中担任定语。不定式作定语时,它的位置在它所修饰的名词或代词之后。I have a lot of work to do. 我有许多事情要做。Have you got anything to say? 你还有什么要说的吗?注意:(1 如果修饰不定代词的还有形容词时,它们的位置应该是:不定代词+形容词+不定式。I have something important to do. 我有些重要的事要做。(2 如果不定式是不及物动词,或者不定式修饰的名词或代词是不定式动词的地点、工具等,不定式之后要加一个介词。This is the best room

8、for you to live in. 这是最适合你住的房间。There is nothing to worry about. 没什么事情可担心的。(3 不定式作定语时,一般可转换为定语从句。to不定式表将来The next train to arrive is from Shanghai. (to arrive=that will arrive(三不定式作副词的用法不定式可起副词的作用,在句中表目的、结果、原因等状语。1.作目的状语to=in order toHe came to teach the little girl English. 他来给这个小女孩上英语课。In order to

9、study English well, she often does more speaking and writing.为了把英语学好,她经常多说多写。2.作结果状语He woke up to find everybody gone.他醒来发现大家都走了3.在某些表示喜,怒,哀,乐等的形容词后作原因状语,可替换为宾语从句。I am very glad to see you .=I am very glad that I can see you.4.在带有enough或too的句子里表程度或结果。不定式的“too+形容词或副词+to do sth.”和“too+形容词或副词+for sb/ s

10、th +to do sth.”结构。She is too young to go to school. 她太小不能上学。(1 tooto结构和tooforto结构连接句子的区别:tooto结构连接两个单句中主语相同的句子。He is too tired. He cant go any further.He is too tired to go any further. tooforto结构连接两个单句中主语不相同的句子。The box is very heavy. She couldnt carry it.The box is too heavy for her to carry.(2 这两种

11、句型还可用sothat(如此以至于结构来连接,构成状语从句. He is so tired that he cant go any further.The box is so heavy that he couldnt carry i t. 不定式的“(not+形容词或副词+enough to”结构和“(not+形容词或副词+enough for sb/ sth to do.”这种结构中不定式也用来作状语表结果.意思是“能够做某事”或“不能做某事”。He is old enough to join the army. 他到参军的年龄了。He is not old enough to go to

12、 school.“(not+形容词或副词+enough to do.”与“tooto”结构可互换。He is too young to go to school.三、“疑问词+不定式”结构-在句中作主语,宾语,表语等who ,which,what,when,how,where(why除外+todo sth(1 作主语-How to get there is a question.(2 作表语-The most important thing for us is to study hard.(3 作宾语-Can you tell me what to do ?(4 作宾语补足语-She ofte

13、n teaches me how to read and write.注意:带特殊疑问句的不定式可跟带特殊疑问词的宾语从句进行句型转换。He didnt know what to do. =He didnt know what he should do.他不知道要做什么。在tell, show, teach, find out, decide, learn, forget等动词之后,常用疑问词+to不定式结构做宾语He doesnt know which one to choose.反馈练习:1. Its very kind _ you _ me _ the classroom.A. of;

14、help;cleanB. of; to help; cleanC. for; to help; to cleanD. for; help; cleaning2. The headmaster will tell us _ next.A. how to doB. what to doC. how do itD. do it3. All of us found _ difficult _.A. it; work outB. its; to work it outC. it was; to work out itD. it; to work out4. We should do something _ sandstorm _ again and again in North China.A. to stop; happenB. prevent; to happenC. to stop; happeningD. keep; happeni