动词不定式基本形式为: to+动词原形,就是老师经常说的 to do有些动词不定式不带to否定形式为:not (to)+动词原形
一提到动词不定式,很多同学只知道表目的,其实它的用法还有很多!
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。如:
For him, to talk with his mother is necessary.
=It is necessary for him to talk with his mother.
动词不定式做表语,常说明主语的内容、性质、特征。常可转换成主语。如:
The best way to improve your English is to join an English club.
=To join an English club is the best way to improve your English.
★可以接带to的动词不定式作宾语的动词主要有:
要求选择同意(ask, choose, agree),
期望决定学习(expect, hope, decide, learn),
宁可拒绝假装知道(prefer, refuse, pretend, know),
希望想要愿意(wish, want/need, would like / love)等。
如:
We decided to talk to some students.
He prefers to eat white bread and rice.
★动词decide, know, learn, show, teach, tell...后可用“疑问词+to的不定式短语”作宾语,但why后面的不定式不带to。如:
Could you please tell me where to park my car?
★动词feel, find, make, think等后面,可以用it作形式宾语代替真正的宾语—动词不定式,句子结构是sb. feel / find / make / ...+ it+adj. / n.+to do...。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,意思差别不太大的动词有begin, start, like, love等。如:
Then I started to watch English-language TV.
I like to eat vegetables.
★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ving形式作宾语,表动作已经发生。
stop to do停下来做另外一件事,stop doing停止做、不做当前这件事;
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。
When I left home, I had forgotten to bring it with me.
I stopped using them last year.
★句子的主语或宾语是动词不定式的逻辑主语,不定式与其所修饰的名词、代词等存在逻辑的动宾关系时,用动词不定式的主动式。
I have so much homework to do today.
It’s a good place to visit.
★作定语的不定式如果是不及物动词,且与所修饰的词之间有动宾关系,要在不定式后加适当的介词。
I need a room to live in.
★在主、被动语态句里用带to的动词不定式作补语的动词主要有:
要求允许提议(ask, allow, advise),
期望邀请鼓励(expect, suppose, invite, encourage),
教导告诉想要(teach, tell, want),
等待希望愿意(wait for, wish, would like / love)。
She asked me not to speak Chinese in English class.
★下列动词,多数动词是感官动词和使役动词,当动词不定式作补语时,在主动语态句里不带to,被动语态句里要将省略的to补上。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。如:
This picture makes me feel tense!
I was made to say sorry to him.
★help后接动词不定式作补语,to可带可不带。如:
Using email 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。如:
He doesn’t seem to have many friends.
Be sure not to miss them if they come to a city near you.
★目的状语,置于句首或句末,置于句首时常表示强调。如:
A group of young people came here to(in order to) discuss this question.
★原因状语,多见于“sb.+be+adj.+to do...”结构句中。如:
I’m sorry to trouble you. I’m glad to see you.
★结果状语,多见于“too...to”,“enough to...”结构句中。如:
Then I’m too tired to do well. What should I do?
The room needs to be big enough for three people to live in.
★独立动词不定式多用作插入语,表示说话人的心理状态或对事情的看法。如:
To be honest, I only eat food that tastes good.
To begin with, she spoke too quickly, and I couldn’t understand every word.
动词不定式的复合结构是“for / of sb. to do sth.”,for / of引出不定式动作的逻辑主语。这种结构在句子中可以作主语、宾语、表语、定语、状语等。
不定式复合结构作主语时,需注意:
It’s + 形容词 + for / of + sb + to do sth.
for前面的形容词是dangerous, difficult, easy, hard, heavy, important, interesting, necessary等,一般说明不定式动作的特性,不说明人的特性。
如:
It’s dangerous for children to swim in the river.
当上面的形容词指的是sb的性质时,用介词of。
这些形容词往往修饰人:careful, clever, foolish, good, kind, nice, wise,bad, polite, careless
It’s very nice of you to say so.
带疑问词的不定式短语动词不定式前面可以带疑问代词what, which, who或疑问副词how, when, where, why等。
这种结构起名词的作用,在句子里用作宾语、主语、表语等,或者单独使用。
I don’t know what to do next.
Where to go is not decided yet.
单独使用时相当于一个特殊疑问句,在复合句中则可变为一个从句。
What to do next? =What will we / you do next?
Can you tell me how to do that?=Can you tell me how I should do that?
动词不定式的否定式不定式的否定式是not to do...,不带to的不定式的否定式是not do...
Sometimes they decide not to talk to each other.
常见的与不定式连用的词组和句型Why not do…?=Why don’t you do …? had better (not) do …
would rather do … prefer to do rather than do
Could/Would/Will you please…? It takes sb +时间/金钱+ to do sth.
It’ s time to do… It’ s one’s turn to…
如: Why not take a holiday?
It takes me an hour to walk there.
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