2.带to的不定式

不定式有带to和不带to的不定式两种情况，在下面的情况下不定式是不带to的。

(1)在情态动词(ought除外)must，can，may，could，might，will，would，shall，should，dare，need之后。

You must be very tired．Did you sleep at all on the plane?(人教大纲版高一上第8页)

你准是累了。你在飞机上没有睡吧?

We needn't stay here this evening．

我们今晚就不必呆在这儿了。

提示：

ought必须和带to的不定式连用:

We ought to learn more about our body and the fuel it needs to keep fit．(人教大纲版高一下第4页)

我们应该更好地了解自己的身体，了解需要什么养分能够维持自己的健康。

但是在否定句和疑问句中，偶尔也可见到ought to中的to被省略的。They ought not(to)do that sort of thing．

他们不应该做那类事。

Oughtn't he(to)send for the police?

他是不是该叫警察呢?

在答语中也可省略:

“Ought he go?”“Yes，he ought(to)．”

“他该走了吗?”“是的。”

(2)在had better(还是……最好)，had best(最好)，would rather(宁可、宁愿)，would rather．．than．．(宁可……而不……)，would sooner(宁可、宁愿)，would sooner．．than．．(宁可……而不……)，cannot but(不得不、必然)，cannot choose but(只得)，cannot help but(不得不)等结构后直接跟动词原形或“not+动词原形”。

If they would rather die，they had better do it．(人教大纲版高三第58页)

他们要是想死，最好让他们去死。

Rather than ride on a crowded bus，he always prefers to ride a bicycle．

他宁愿挤公共汽车也不愿骑自行车。

Liu Hulan would sooner die than surrender．

刘胡兰宁死不屈。

One's world outlook cannot but come through in what one says and does．

一个人的世界观必然在他的言行中表现出来。

(3)在“使役动词+宾语”之后的宾语补足语中。这些词主要有let，make，have等。

We know that we cannot let physical disabilities limit a person's life．(人教大纲版高二下第51页)

我们懂得我们不能让身体的残疾来限制一个人的生活。

We will not let our history and culture be destroyed．(人教大纲版高一上第45页)

我们不能让我们的历史和文化就此毁灭。

I had Xiao Hua wash my clothes．

我叫小华洗了我的衣服。

提示：

必须指出，动词have通常不用于被动语态。当make用于被动语态时，不定式要有to;当let用于被动语态时，后跟单音节(双音节和多音节的词除外)的不定式时，不定式一般不带to。

He was made to tell me everything．

他被迫说出了全部实情。

The prisoners were let go．

那些犯人获释出狱了。

(4)在“感官动词+宾语”之后的宾语补足语中。这些词主要有see，hear，look at，listen to，notice，watch，feel，observe等。

I've seen your nobler aspirations disappear one by one，until only one，Gain，was left．(03人教高三第61页)

我看到你崇高的愿望都在渐渐消失，到现在只留下“获利”愿望了。

When deciding which species to save，and which to watch die，Root said one key is the uniqueness．

鲁特说，决定挽救哪个物种，任哪个物种灭亡的关键之一是要看其独特性。

提示：

在which to watch die中，which在逻辑上作watch的宾语，die作其宾补。

I felt the house shake．

我感觉房子在晃动。

Look at that boy jump!

看，那个孩子在跳!

Do you like listening to other people talk?

你喜欢听他人说话吗?

提示：

但在被动语态中要加上to。

He was seen to enter the house．

有人看见他进了房子。

I was listened to by them to repeat what Uncle Li had said the day before．

他们听我把李大伯头天说的话又讲了一遍。

(5)在help或“help+宾语”之后，既可带to，又可不带to。

Chemical fertilisation，for example，helps to produce better crops，but is harmful to the environment．(人教大纲版高一下第45页)

比如化肥可以增加收成，但有害于环境。

For some，medicine can help keep them alive，but the treatment is expensive and does not cure them．(人教大纲版高二上第51页)

有些人可以靠药物维持生命，但治疗费用昂贵，而且无法根治。

Being an exchange student helps you make friends with people from different backgrounds and understand another culture．(人教大纲版高三第71页)

当一名交流学生有助于你跟不同文化背景的人交朋友，并了解另外一种文化。

Travel agents can help you to find out about package trips that include hotel costs，tours and entrance tickets and to choose between different alternatives．(人教大纲版高二下第39页)

旅行社会帮助你了解包括宾馆开支和景点门票在内的全包式旅游，也可以帮你选择其他的旅游方式。

(6)在介词except/but之前有动词do的某种形式，其后的动词不定式常常不带to。

Last evening I did nothing but repair my farm tools．

昨晚我除了修理农具外，没有做其他的事情。

Now there was nothing he could do except admit defeat．

现在他只有认输。

提示：

如but之前没有do，其后的不定式则一般要加to。I'm afraid we have no choice but to take a taxi．

恐怕我们别无选择，只好乘出租车了。

They desired nothing but to succeed．

他们只想成功。

(7)在why引起的一些疑问句中，疑问词直接跟不带to的不定式，或“not+不带to的不定式”。

Why spend so much money?

为什么花这么多钱?

Why read，and sometimes even write poetry?(人教大纲版高二上第31页)

为什么要读诗歌，甚至有时还要写诗呢?

Why not let her have a try?

为什么不让她试一试?(表示建议)

Why not do some experiments?

做些实验吧。

Why stand there if you can sit down?

你本可以坐下，为何偏偏站着?

(8)当用于过去时、现在完成时或过去完成时的know表示“听见”、“看见”或“经历”的意义时，作宾补的不定式以不带to的形式居多，偶见带to的不定式。

I've known him walk with—I've known him walk with Tiny Tim upon his shoulder，very fast indeed．(人教大纲版高三第62页)

我看到他走路走得挺快的——他边走边背着小蒂姆呢。

I have never known him sing so beautifully before．

以前我还从来没有听见他唱得这样好。

I never knew him do anything without a good reason．

我还没有听说过他没有一个合适的理由就去做某件事的。

Have you ever known her lose her temper?

你有没有看到过她发脾气?

提示：

①但在被动结构中要带to。

He's sometimes been known to sit there all day．

有时能见到他整天坐在那里。

②表示“看见”、“听见”或“经历”意义的know后面的宾补通常是动态

动词，静态动词作宾补时，总是带to的;如果宾补是不定式的完成式，也必须带to。

I have never known him to be too busy to study．

我从未看到过他忙得没有时间学习的。

They knew the man to have been a thief．

他们发现此人曾是小偷。

③know表示“知道”，后面也可以跟不定式作宾补，这个时候know后面的不定式无论是主动语态还是被动语态都是带to的，且不定式的动词有如下两个特点:一是跟不定式的一般式作宾补时，多半是静态动词(to be最为常见);二是还可以跟不定式的完成式。

请仔细观察和对比:

I know him to be a fool．

我知道他是傻子。

He is known to be honest．

=Everybody knows that he is honest．

=It is known that he is honest．

大家都知道他是诚实的。

He was known to have taken money from the Germans．

=We knew that he had taken money from the Germans．

=It was known that he had taken money from the Germans．

听说他曾拿走了德国人的钱财。

(9)当主语部分出现了动词do的某种形式，后面的表语既可带to，也可不带to。

All we have to do is clean or peel them．(人教大纲版高一下第6页)

我们只需将它们洗干净，剥掉皮就可以吃了。

One of the most important things we must do is to make sure that children who are affected by the disease receive the help and care that they need．(人教大纲版高二上第127页)

我们要做的一件事就是要保证受到这种疾病影响的孩子能够得到他们所必需的帮助和照顾。

All we have to do is to be careful how often and how much we eat of it．(人教大纲版高一下第75页)

我们必须留意我们间隔多久吃一次(垃圾食品)，每次吃了多少。

What the plan does is(to)improve our living conditions．这项计划的作用是改善我们的生活条件。

All I did was empty the bottle．

我只是把瓶子倒空了而已。

提示：

在上述结构中，如果do是完成式，后面的表语部分也可采用-ed形式;如果do是进行式，则表语部分必须采用-ing形式。

What he's done is spoil the whole thing．

=What he's done is to spoil the whole thing．

=What he's done is spoiled the whole thing．

他什么也没做，就是弄糟了整个事情。

What he is doing is spoiling the whole thing．

他现在所做的把整件事情都弄糟了。

(10)动词原形come，go等在口语中可接不带to的不定式。

You might as well go stand upon the beach and argue with the sea．(人教大纲版高二下第67页)

你还不如站在海滩上跟大海讲理去。

Come have a glass．

来喝一杯。

(11)在出现并列的动词不定式时，为了避免重复，后面的不定式符号to可省略。

I really don't know what to say and do．

我真的不知道该说什么，该干什么。

Young，beginning artists and musicians often do not have enough money to rent studios or other buildings to practise，perform or even work and live．(人教大纲版高二上第23页)

年轻的、刚起步的艺术家和音乐家往往没有钱租用画室或者排练和表演的场所，甚至连工作和生活的场所都没有。

提示：

但如果两个不定式有对比的意思，则不定式符号to不可被省去。I came not to scold you but to praise you．

我是来夸你的，不是来骂你的。

The purpose of the new technology is to make life easier，not to make it more difficult．

这项新技术旨在让生活更加便捷，而不是让生活更加麻烦。

当然，出现并列的动词不定式时不省略to也是常见的。