动词不定式的归纳

动词不定式的归纳

编写Johnplay Saturday, November 23, 2013

动词不定式由to +动词原形组成,在句子中具有名词、形容词和副词的特征,因此在句中可以作主语、表语、宾语、定语、状语、宾补。

㈠不定式作主语

动词不定式在作主语时,用法主要有以下几种：

⑴动词不定式作主语时,常用it作形式主语,而往往将动词不定式放在谓语或表语之后。如：①It's not easy to learn a foreign language well.

=To learn a foreign language well is not easy.学好一门外语不容易。

②It is dangerous To lean out of the window

=To lean out of the window is dangerous.身子探出窗外很危险。

⑵ It takes sb+some time+to do用it作形式主语,把真正的主语不定式置于句后。如：

①How long did it take you to finish the work? 你花了多少时间来完成这项工作吗？

②It will take us half an hour to get there by bike 我们骑自行车到那里将要花半小时。

⑶It+be+形容词+for sb+to do，常用表示客观情况的形容词，如：difficult, easy, hard, important, impossible, necessary等.

①It's difficult for us to finish the work. 对我们来说，完成这项工作很困难。

②It's hard for me to answer your question. 要我回答你的问题很难。

⑷It+be+形容词+of+ sb+to do常用careless, clever, good, foolish, honest, kind, lazy, nice, right, silly, stupid, wise等描述行为者的性格、品质的形容词,则应在不定式前加一个of引起的短语。☻注意：在of sb.结构中,可用sb.直接作句子的主语来改写。试比较：

①It's foolish of him to go alone. (=He was foolish to go alone.) 他单独出去太傻了。

②It's kind of you to give me the book. (=You are kind to give me the book.)你给我这本书,真是太好了。

⑸It seems(appears)+形容词+to do

It seemed impossible to save money. 现在好像不可能存钱。

⑹It+be+名词+to do

It's our duty to take good care of the old.照顾老人是我们的责任。

⑺不定式的完成式也可作句子的主语

①To have made the same mistake twice was unforgivable.两次犯同样的错误是不可原谅的。

②It is better to have loved and lost than never to have loved at all.

爱过而后失去了爱,比从未爱过要好。

⑻疑问词who,which,when,where,what等常与不定式连用,在句中起名词作用,可充当主语、宾语、表语等。

①How to solve the problem is very important．(主语) 如何解决这一问题很重要。

②He didn’t know what to ask．(宾语) 他不知道该问些什么。

③ My question is when to start．(表语) 我的问题是何时开始。

㈡不定式作表语

☻不定式可放在be动词后面,形成表语,如：sb+ is to do sth。如：

①My work is to clean the room every day. 我的工作是每天清扫房间。

②His dream is to be a doctor.他的梦想是成为一名医生。

☻可用主动形式表示被动含义的结构有to blame, to let.

①Who is to blame? 谁该受到责备？②The house is to let. 该房屋出租。

③Suspects are still to find out. 凶手还有待查明。

㈢不定式作宾语

⑴不定式做宾语时须注意：不定式并不是可做任何及物动词的宾语。能接不定式做宾语的动

词有：afford付得起,agree同意，appear显得,arrange安排,ask要求,attempt试图,choose决定,claim声称，condescend屈尊,consent准许，decide决定,demand要求,determine决心,endeavor 竭力,expect期待,fail未履行,help帮助,hesitate犹豫，hope希望，learn学会,manage设法，neglect 疏忽,offer主动提出,plan计划,prepare准备,pretend假装，proceed接着做,promise答应，prove 证明，refuse拒绝，resolve解决，seem觉得好像,swear发誓,tend往往会,threaten预示,undertake 承诺,volunteer自愿做,vow发誓,want想要,wish希望,等。如：

①She managed to avoid an accident. 她设法避免了一次事故。

②I can’t afford to buy such an expensive computer. 我买不起这么昂贵的电脑。

③He pretended not to know the facts. 他佯装不知实情

⑵做宾语的不定式如果带有自己的补足语,则须用it做形式宾语,而将真正的宾语置于补足语之后,即:主语+动词+it+补语+to do句式。如：

Do you think it necessary to master a foreign language? 你认为掌握一门外语有必要吗？

I find it interesting to stay with you. 我发觉与你呆在一起很有趣。

⑶动词+疑问词+不定式,这类动词常见的有：tell, advise, show, teach, find out, decide, discuss, learn, forget, inquire, know, explain, remember, see, understand, wonder等。如：

①Please show us how to do that. 请演示给我们如何去做。

②There are so many kinds of tape-recorders on sale that I can't make up my mind which to buy.有这么多的录音机，我都拿不定主意买哪一种。

㈣不定式作宾语补语

☻不定式作宾语的补足语须从二个方面来掌握。

⑴动词接动词不定式做宾语的补足语时,不定式的to不能省略。这样的动词有：advise, allow, ask, beg, cause, encourage, expect, force, forbid, get, help, order, permit, persuade, require, teach, tell, want, wish, warn, call on, wait for, long for。如：

①The teacher advised us to learn through experiment. 老师劝我们通过实验来学习。

②They didn’t allow us to enter the hall. 他们不允许我们进入大厅。

⑵常接不带to的不定式作宾语补足语的动词或短语有:一感(feel),二听(hear,listen to),三让(have,let,make),五看(look at,notice,observe,see,watch)但是这些句子变成被动语态时,需带上to ①主动：The boss made the workers work over ten hours a day in the past.

→被动：The workers were made to work over ten hours a day by the boss.

过去老板使工人们每天工作十多个小时。

②主动：I saw Li Lei fall down from his bike.

→被动：Li Lei was seen to fall down from his bike.我看见李蕾从单车上摔了下来。

☻注意：help后的宾语补足语可以带to也可以不带to。如：

He often comes to help us (to) do some farming work. 他经常来帮我们干农活。

㈤不定式作定语

动词不定式作定语需后置，与所修饰的词有主谓或动宾关系。

①When the question was out,he was the first one to raise his hand.问题一提出,他第一个举手。

②This terrorist attack is a lesson to remember. 这次恐怖袭击事件是个应该记取的教训。

③I am afraid I cannot attend your party,for I have too many things to do.恐怕我不能参加你的晚会了,因为我有好多事情要做。

注意:☻当被修饰的是不定代词.如:everything, anything, much, little等,或被修饰的名词前被形容词最高级,序数词,the only等强调结构修饰时,非谓语动词作定语则只能用动词不定式。He was the last to realize the importance of this problem. 他没有及时意识到问题的重要性。