(六)非谓语动词常考的其他结构

(1)疑问词+不定式结构。

疑问词who,what,which,when,where,和how后加不定式可构成一种特殊的不定式短语。它在句中可以用作主语、宾语、表语和双重宾语。如：

When to start has not been decided.何时动身尚未决定。(主语)

I don?t know what to do.我不知道该怎么办。(宾语)

The difficulty was how to cross the river.困难在于如何过河。(表语)

I can tell youswheresto get this book.我可以告诉你哪里可以买到此书。(双重宾语)〈注〉a.有时疑问词前可用介词，如：

I have no idea of how to do it.我不知道如何做此事。

b.动词know后面不能直接跟不定式作宾语，只能跟疑问词(如：how,what)+不定式。如：

While still a young boy,Bizet knew how to play the piano well and as he grew older, he wrote operas,the most famous of which is Carmen.

(2)动词不定式的几个重要时态。

A.不定式的完成式。

动词不定式的完成式常在动词appear,happen,pretend,seem等之后体现它所表示的动作发生在谓语动词所表示的动作之前。但在be,wish,intend,mean,plan,hope,expect,should或w

ould like等动词之后，则表示没有实现的行为。例如：

I am sorry to have kept you waiting.对不起让你久等了。

She seemed to have forgotten her promise.她似乎把她所答应的事给忘了。

He pretended to have read the book.他假装读过这本书。

He planned to have gone abroad.他原计划出国(但他没有去)。

I hoped to have seen her.我原希望会见到她的(可是我没见到她)。

I would like to have had your help.我本想得到你的帮助(实际上我却没有得到)。

The enemy expected to have found him.敌人本来指望找到他(实际上却没有找到)。

I intended to have finished my work last night.我本想昨晚完成作业。

We were to have sailed next morning.我们本定于第二天早上启航。

而在acknowledge,believe,consider,find,know,report,say,suppose,think,understand等动词之后跟不定式的完成式时，这些谓语动词用被动语态形式。

The bank is reported in the local newspaper to have been robbed in broad daylight yesterday.

Byron is said to have lived on vinegar and potatoes.

B.不定式进行式和完成进行式。

不定式进行式表示其主要谓语动词所代表的动作(情况)发生时，不定式所表示的动作正在发生；不定式完成进行式表示其动词所代表的动作，在主要谓语动词所代表的动作之前一直在进行。如：

When he came in,I happened to be doing my experiment in the lab.当他进来时，我刚好正在实验室做实验。

Why do you stand here?you are supposed to be working in the lab.为什么你站在这儿?现在你应该正在实验室工作。

The students are said to have been investigating the possibility of producing the new product.据说学生们一直在调查生产新产品的可能性。

They are quite happy to have been cooperating harmoniously with us till now.他们非常高兴一直和我们愉快地合作到现在。

(3)不带to的不定式。

A.在表示生理感觉的动词后的不定式不带to。这类词有：

feel觉得observe注意到，看到overhear听到watch注视notice注意listen to听see看见hear听perceive察觉，感知look at看

B.另一类是某些使役动词，如make,let,have等。如：

Let him do it.让他做吧。

I would have you know that I am ill.我想要你知道我病了。

〈注〉：

①上述感觉动词与使役动词转换为被动结构时，其后的不定式一般需带to,如：

He was seen to come.别人看到他来了。

The boy was made to go to bed early.男孩早早被打发上床睡觉。

②在动词find与help之后，不定式可带to亦可不带to，如：

He was surprised to find the sheep(to) break fence at this season.他发现羊在此季节越出栅栏，感到惊讶。

C.在do nothing/anything/everything but (except)结构中。例如：

Last night I did nothing but watch TV.昨天晚上，我除了看电视别的什么也没有干。

John will do anything but work on a farm.除了农活，约翰什么都愿意干。

但是，如果谓语动词不是“do nothing,anything,everything”,那么but (except)所跟的不定式则仍须带“to”。例如：

The doctor told him nothing but to stop smoking.医生除了让他戒烟，其他什么都没有说。

There was nothing for them to do but to remain silent.除了保持沉默以外，他们没有别的办法。

(4)不定式与动名词的逻辑主语和分词独立结构

A.不定式的逻辑主语为：for+名词(或代词宾格)+不定式。例如：

I found it impossible for him to do the job alone.我发现他一个人干这活是不可能的。

〈注〉在表示人物性格、特性等的形容词后面，常用of引出不定式的逻辑主语。例如：

It was wise of him to do that.他那样做是明智的。

B.动名词的逻辑主语为：①人称代词的所有格+动名词；②名词?s+动名词。例如：

Tom insisted on my going with them.汤姆坚持要我和他们一起去。

He dislikes his wife?s working late.他不喜欢他妻子工作到很晚。

C.某些形容词，如：careless,clever,considerate,foolish,good,impolite,kind, naughty,nice,silly,stupid等不定式后可以加of来引导出其逻辑主语。

It is very kind of you to help me.你帮助我太好了。

间或也可用for+there to be表示(而且there后面的不定式只能是to be)。

It?s a great pity for there to be much trouble in the company.太遗憾了公司里有这么多的麻烦。