动词不定式用法
一、动词不定式的基本形式是“不定式符号to+动词原形”,有时可以不带to。动词不定式没有人称和数的变化。在句中不能单独作谓语,但仍保留动词的特性,可以有自己的宾语、状语等。动词不定式同它的宾语和状语一起构成不定式短语。
例如:to sell flowers in the street 在街上卖花
to speak in the classroom 在教室里讲话
不定式省to有四种情况:
1、使役动词let,make,have等后接不定式。
例如:Let him go!
The boss made the childlabors work the whole night.
2、would rather,had better后。
例如:You had better stay at home.
3、Why…/Why not…后。
例如:Why not have a good rest on Sunday?
4、感官动词see,watch,look at,hear,listen to,smell,feel,find,notice 等后作宾语补足语,省to。
例如:I saw him dance.
注意:这些情况在被动语态中,不可省to.
例如:The childlabors were made to work the whole night.
二、动词不定式具有名词、形容词和副词的特征,可以作句子的主语、表语、宾语、宾语补足语、定语和状语。
1、用作主语
直接把动词不定式置于句首的情况不多,多数情况用it作形式主语,把真正的主语——动词不定式置于句末,特别是不定式短语较长时。动词不定式作主语,谓语动词用第三人称单数形式。带疑问词的不定式短语作主语常置于句首。
例如:The head teacher said it was necessary to talk with his mother.
How to make requests
politely is important.
2、用作表语
动词不定式作表语,常用在be动词及seem,appear,happen等词之后,构成系表结构。说明主语的内容、性质、特征。
例如:The best way to improve your English is to join an English club.
She seem to be well-known.
3、用作宾语
. 用作宾语的动词不定式,常用在动词ask, choose, agree,expect, hope, decide, learn,prefer, know,wish, want, would like / love等及物动词之后,构成动宾短语。
例如:We
decided to talk to some students about why they go there.
He prefers to eat white bread and rice.
I’d love to visit Mexico.
.动词feel, find, make, think,believe等,在语法上不能接受不定式作宾语,只有用it作形式宾语,从而把动词不定式后置。句子结构是:主语+feel / find / make / ... it+adj. / n.+to do...。
例如:I find it difficult to remember everything.
.既可接动词不定式又可接v-ing形式作宾语,意思差别不大的动词有begin, start, like, love等。一般说来,动词不定式表一次、数次的具体动作的全过程,v-ing形式表习惯性的连续动作。但这种区别并不很严格,特别是美式英语,即使是习惯性的动作也可以用动词不定式。
例如:Then I started to watch English-language TV.
I’m
beginning to understand my Chinese roots, and who I am.
(begin用了进行时态,后面只接不定式作宾语,表示事情刚开始,还要继续下去。)
.后接动词不定式或v-ing形式作宾语,意思差别较大的动词有forget, remember等。后接不定式作宾语,表动作尚未发生;后接v-ing形式作宾语,表动作已经发生。stop to do停下来做另外一件事,to do是目的状语;stop doing停止做、不做当前这件事,doing是宾语。try to do尽力做,try doing试试看;go on to do接着做另外的事,go on doing继续做原来的事。
例如:When I left home, I had forgotten to bring it with me.
I stopped using them last year.
后只接v-ing作宾语的一些常用特殊动词:give up,enjoy,practise,finish,mind等。
例如: Would you mind
opening the window?
4、用作定语
用作定语的动词不定式一般都位于被修饰的名词之后。
例如:I have so much homework to do today.
I cant think of any good advice to give her.
通常chance,place, time, way等名词后接不定式作定语。另外在the first,the second,the last,the only等词后,也常用不定式作定语。
例如:He needs time to do homework.
You want to know the best way to get around the city.
5、用作补语
.常见动词不定式作宾语补足语的动词主要有:要求允许提议警告(ask, allow, permit, advise,warn),期望邀请鼓励(expect, suppose, invite, encourage),教导告诉想要(teach, tell, want),希望愿意( wish, would like / love)。
例如:I invited her to have dinner at my house.
Teenagers should be allowed to choose their own clothes.
.动词不定式作补语,在主动语态句里不带to,被动语态句里带to时多数动词是感官动词和使役动词,包括四“看”:look at, observe, see, watch,三“让”:have, let, make,二“听”:hear, listen to,一“感觉”:feel,一“注意”:notice。
例如:This picture makes me feel tense!
Of course we want to see Liu Yu
achieve his dreams.
.help后接动词不定式作补语,to可带可不带。一般说来,带to表间接帮助,不带to表直接帮助。在被动语态句里,或者用不定式的否定式作补语时要带to。
例如: They can help you to compare two different products so that you can buy the one you really need.
Using e-mail English helps you write quickly.
.be said, be sure, happen, seem等后面可以接带to的动词不定式作主语的补语。
例如:He doesn’t seem to have many friends.
Be sure not to miss them if they come to a city near you.
6、用作状语
.目的状语,置于句首或句末,置于句首时常表示强调。为加强语气,常与in order或so as 组成短语。
例如:A group of young people got together to discuss this question.
In order to help him,we would do everything we can.
注意:置于句首时只用to do / in order to do。
.原因状语,多见于“sb.+be+adj.
生词表: