[高中]全新语法:动词不定式 四、不定式特殊句式

四、不定式特殊句式

1.疑问词+to do sth.

（1）做主语

Where to go tomorrow has not been decided.明天到什么地方去尚未决定。

It is still a question how to divide labor among the workers.

这些工人之间如何分工仍是个问题。

When to start still remains a question.何时出发还是个问题。

it still remains a question when to start.何时出发还是个问题。

（2）作动词宾语

I know where to find the boy.我知道到哪里能找到这个男孩。（作动词know的宾语）

I asked her how to learn English.我问她如何学英语。（作直接宾语）

Will you please show me how to get to the nearest bank？

你能告诉我去最近的银行怎么走吗？（作直接宾语）

【提示】 动词show，know 只能用“疑问词+to do”不定式短语作宾语。

（3）作介词宾语

He has no idea of how to answer this question.他不知道怎样回答这个问题。

He thought a lot about how to improve the crop.他对如何提高收成考虑得很多。

We must first solve the problem of whom to serve.我们必须首先解决为谁服务的问题。

【提示】 有时定语从句也可以简化为“介词+which （关系代词）+to do sth.” 形式。

Della had only $1.87 with which to buy Jim a present.德拉仅有$1.87来为吉姆买一件礼物。

You have a number of topics from which to choose.你有很多题目可以选择。

（4）作表语

The question is which to choose.问题是挑选哪一个。

The most difficult challenge is how to survive without friends.

最难的挑战，就是生活中孤独无友。

2.for sb.to do sth.

（1）作主语

It is important for you to find a job.对你来说找份工作是重要的。

It isn’t right for people to laugh at others.人们嘲笑别人是不对的。

【提示】 for后的sb.是动词不定式的逻辑主语，即to do这一动作的执行者。

（2）作宾语

I consider it necessary for her to learn French.我认为她需要学法语。

We must try to make it possible for lost time to be recovered.

我们必须努力夺回失去的时间。

【提示】 “for sb.to do ...”作宾语时，常用it作形式宾语。

（3）作表语

It’s for you to decide what to do next.得由你来决定下一步该做什么。

What I want is for you to have a rest.我希望的是你先休息一下。

（4）作定语

It’s time for us to go to bed.现在是我们睡觉的时候了。

There’s no reason for you to be late.你没有理由迟到。

（5）作状语

He stood aside for her to pass.他站在一边让她过去。（作目的状语）

The lesson is too easy for them to read.这一课对他们来说太容易了。（作结果状语）

3.It is+形容词+for sb.to do sth.

certain 肯定　　　　　clear 清晰的　 　　dangerous 危险的　　　　　difficult 困难的

easy 容易的　　　　　 fit 恰当的　　　 　hard 艰难的　　　　　　　 important 重要的

impossible 不可能的　 illegal 非法的　　　legal 合法的　　　　　　　likely 可能的

necessary 必要的　　　obvious 明显地　　　possible 可能的　　　　　 proper 合适的

suitable 适当的　　　 useful 有用的

It’s impossible for me to be with you.同你在一起我觉得不可能。

It’s very dangerous for children to cross the busy street.

对孩子们来说，穿过繁忙的街道很危险。

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

It is necessary for us to master a foreign language.对我们来说精通一门外语是必要的。

4.It is+形容词+of sb.to do sth.

brave 勇敢的　　　　　careful 细心的　　　　　careless 粗心的　　　　　clever 聪明的

considerate 体贴的　　crazy 疯狂的　　　　　　cruel 残忍的　　　　　　 foolish 傻的

good 好的　　　　　　 honest 诚实的　　　　　 impolite 没礼貌的　　　　kind 善良的

lazy 懒惰的　　　　　 naughty 淘气的　　　　　nice和蔼的　　　　　　　 polite 有礼貌的

right 正确的　　　　　rude 粗鲁的　　　　　　 selfish 自私的　　　　　 silly 愚蠢的

stupid 笨的　　　　　 unkind 不友好的　　　　 unselfish 无私的　　　　 unwise 不明智的

wise 聪明的　　　　　 wrong 错误的

It is very kind of you to help me out.帮我们摆脱困境太感谢你了。

It seemed selfish of him not to share his dictionary with others.

他很自私不和其他人共用他的词典。

It’s silly of you to do such a thing.做这样的事你真傻。

It’s wrong of the other children to make fun of you.别的孩子取笑你是不对的。

【提示】

“It is+形容词+of sb.to do sth.” 句式中，of的宾语可变为主语，不定式作状语的句式。

It is careless of him to lose so many things.他丢了这么多东西，真是太粗心了。

He is careless to lose so many things.

【辨析】有个好身体对我们来说是很重要的。

【正】It is important for us to have good health.

【误】It is important of us to have good health.

【误】We are important to have good health.

5.be to do sth.

（1）打算、决定、计划、安排等。

He is to visit Japan next week.他决定下周访问日本。

I was to have told you yesterday，but you were not in.

我本打算昨天告诉你的，但你不在家。

【提示】 be to have done表示本打算干，事实上没有干成。

I was to have seen him last Wednesday but he did not come.

我本来上周三就能见到他的，可他没来。

（2）指示、命令、禁止等，意为“必须，一定”。

You are to hand in the exercises tomorrow.你们明天必须交练习。

You’re not to smoke here.你不可以在此处抽烟。

（3）责任、义务、需要，意为“该不该”。

Who is to blame？ 谁该负责？

You are to report to the police.你应该报警的。

（4）可能性，与can，may 相当，不定式多用被动式。

The book was not to be found.那本书可能找不到了。

the book could not be found.

（5）假设，用于虚拟条件句中。

If it were to rain，we would get wet.要是下雨，我们就会淋湿。

If I were to meet her tomorrow，I would ask her about it.

若是明天能见到她，我就会问她这件事。

（6）be about to do 刚打算，即将做

I was about to speak when Mary spoke first.我正要讲话，玛丽先开口说了。

I was on the point of speaking when Mary spoke first.

【提示】 be about to不与具体的时间状语连用。

6.be said to do sth.

They are said to leave soon.据说他们很快就要离开。（将来）

His company is said to be in trouble.据说他的公司遇到了困难。（现在）

He is said to be doing fine at school.据说他在学校表现很好。（现在）

They are said to have left London.据说他们已经离开伦敦。（过去）

There is said to be plenty of oil off our coast.据说我国沿海有大量的石油。（现在）

There is said to have been an earthquake in Japan.据说日本发生了一次地震。（过去）