(经典)动词不定式的精讲与专项练习

动词不定式（The Infinitive）
二、不定式的主要用法
动词不等式具有名词、形容词及副词的特征，因此在句中可作主语、宾语、宾语（或主语）补足语、表语、定语、及状语等。

1、不定式作主语
①不等式作主语时，谓语动词用单数形式。

To conquer English is not easy. 征服英语不容易。

To make plan firs t is a good idea. 先制定计划是个好主意。

To know everything is to know nothing. 事事皆通，无一精通。

②不等式作主语时，常常用形式主语it替代，而将真正的主语不等式放在句子的后面。

It is necessary to master a foreign language.掌握一门外语很有必要。

It’s a great pleasure to see you again.再次见到你真高兴。

It is a bad manner to stare at a foreign guest.盯着外宾看是一种不良的举动。

③如果说明不等式表示的动作是谁做的，可以在不等式的前面加一个for引起的短语，这就是常见的“It is adj./n. for sb. to do sth.”
句式。

如：
It is good manners for an Arab to stand close to his friends when they are talking.
对阿拉伯人来说，交谈时站得离朋友近些是好的礼貌。

It is a great honor for us to be presented at the party.我们能来参加晚会，深感荣幸。

It will be a regret for us not to help him. 我们没有帮助他是个遗憾。

④在某些形容词（如kind, good, nice, wise, unwise, clever, silly, wrong, right, foolish, stupid, careless, considerate, rude, naughty, impolite等）作表语时，不等式前常加一个以of引起的短语，来说明不等式指的是谁的情况。

这就是常见的“It is adj. of sb to do sth.”句式。

如：
It’s very kind of you to think so much of us. 谢谢你替我们考虑这么多。

It is unwise of them to do like that. 他们那样做是不明智的。

It’s impolite of you to gossip about others.你们说别人的闲话是不礼貌的。

It’s careless of them to ignore this important point.他们忽视了重点，只是粗心。

2、不定式作宾语
①英语中能以不等式作宾语的动词很多。

常见的有：like, want, wish, hate, prefer, hope, manage, try, offer, start, ask, forget, promise, pretend, intend, begin, attempt, decide, desire, agree, learn, choose, expect等等。

如：
Don’t forget to bring your dictionary.不要忘记把你的字典带来。

He can’t afford to buy a car.他买不起小汽车。

I need to fetch a tape from a friend. 我需要去一个朋友处取一盒磁带回来。

We’ve decided to put on a short play next week. 我们决定下一周演一个小话剧。

Once you start to smoke, you cannot easily give it up. 一旦你抽上了烟，你就不容易戒掉。

I really like to watch football matches. 我非常喜欢看足球比赛。

How I wish to see my old friends again. 我多么想再见到我的老朋友啊！
②当不等式作直接宾语，而后面还有宾语补足语时，通常把不等式放在补足语后面，而用形式宾语it来替代它。

如：
I found it impossible to answer all the questions within the time given.我发现在限定的时间内回答所有的问题是不可能的。

She thought it unnecessary to argue with him about it.她觉得没有必要和他辩论这问题。

He made it a rule only to speak English in class. 他规定课上只能说英语。

I find it necessary to speak about our shortcomings. 我觉得有必要谈谈我们的缺点。

She feels it hardly to help others. 她认为帮助别人是她的责任。

③英语中介词后面通常要用动词的动名词形式。

但是下面的这些短语中的介词却例外：be about to +不等式，do nothing but, cannot help choose but, nothing except, nothing else than，cannot but 等。

如：
He is about to go aboard to study. 他将出国学习去了。

The patient can not but follow the doctor’s instructions, though he doesn’t think it necessary.
病人只得遵照医生的嘱咐，尽管他们认为没有必要。

These children did nothing except play all day long. 这些孩子除了整天玩外，什么都没做。

He did nothing else than laugh. 他只是笑。

He does everything except go to school. 他怎么也不上学。

I had no choice but to give up this chance to go aboard. 我没有办法只好放弃了此次出国的机会。

I have got nothing to do but depend on myself. 我没有办法只好依靠自己。

★ [注意] but、except用作介词（除……之外）接不等式，如前面有do/does/did时，不等式不带to，否则要带to。

再如：The lady can do nothing but give in. = The lady has no choice but to give in.
3、不定式作宾语补足语
在很多句子中，不定式用作宾语（名词或代词）的补足语，从而构成复合结构，即复合宾语。

句子的宾语与不定式之间在逻辑上是主谓关系。

这坟种情况：
①带to的不等式作宾语补足语。

要求带这种结构的常见动词有：
ask 要求 want 想要 order 命令 tell 告诉 like 喜欢 get 使allow 允许
know 知道
help 帮助
persuade 说服
advise 建议
permit 允许
teach 教
beg 祈求
warn 警告
encourage 鼓励
forbid 禁止
cause 导致
invite 邀请
force 逼迫
require 要求
wish 希望
warn 警告
request 要求
forbid 禁止
invite 邀请
cause 导致
advise 劝告
urge 敦促；促使
The teacher asked us to recite the texts. 老师要我们背诵课文。

We didn’t want this to happen. 我们并不希望发生这样的事。

I told Jeff to join the club, but he wouldn’t listen. 我告诉Jeff让他加入俱乐部，但他不听。

I expected her to arrive on Sunday. 我希望她星期天到。

They encouraged me to try again. 他们鼓励我再试一次。

I’ll get someone to repair your bike. 我去找个人来帮你修自行车。

②不带to的不等式作宾语补足语。

要求带这种结构的常见动词有（但这些动词的被动形式需要带to）：
see 看见notice 注意watch 仔细看look at 看见
discover 发现
observe 观察
hear 听见
listen to 听
feel 感觉
make 使
let 让
have 让
Nothing will make me change my mind. 什么也改变不了我的注意。

Nobody saw him come in.谁也没看见他进来。

We listened to the band play in the park.我们在公园听乐队演奏。

She was seen to enter the room about the time he was leaving. 他走的时候看到她进入房间。

★特别注意：上述这些动词的被动语态一定要加上to.
另外，主动语态动词help后的复合宾语中的不等式可带to，亦可不带to.而被动语态必须加to
She often helps her parents (to) wash clothes. 她经常帮爸妈洗衣服。

= Her parents are often helped to wash clothes.
I won’t be made to change my mind by anything.
He wasn’t seen to come in by anyone.
The band was listened to play in the bank.
③有些成语动词后面的复合宾语中用带to的不等式；常见的有：wait for, call on, count on/upon, vote for, rely on, depend on/upon, long for, care for, prevail upon等。

但是在listen to, look at后面的复合宾语的不等式则不带to.
I’m counting on him to help me through. 我指望他能我度过难关。

We’ll vote for Mike to be our monitor.我们将头迈克的票，选他当班长。

Don’t count on us to give you any help. 别指望我们能给你任何帮助。

We are interested in looking at him play football. 我们看到他们踢足球感到很有趣。

We are longing for the new season to begin soon. 我们都渴望新的赛季快的开始。

④有些动词后跟复合宾语，但这种宾语中的不定式多由to be + adj构成，常见的有think, consider, find, believe, suppose,
know, feel, understand, declare, take等。

但在think，consider, find后又可以直接加形容词，而不用to be。

如：She felt that to be the highest praise.她认为这是最高的赞扬。

She considered that to be important. 她认为这很重要。

I know that not to be true. 我知道这不是真的。

They find the answer (to be) quite satisfactory. 他们对答复感到很满意。

We don’t consider his plan (to be) practical. 我们并不认为他的计划是可行的。

She imagined herself to be cleverer than others. 她自以为自己比别人都要聪明。

4、不定式作主语补足语
①含有宾语补足语的句子变成被动结构时，原句中的宾语变成了被动语态的主语，原先宾语补足语变成了主语补足语。

He asked me to be patient. 他要我耐心点。

[me为宾语，不等式作宾补]
I was asked to be patient. 我被要求耐心点。

[I为主语，不等式作主补]
The answer was found to be quite satisfactory. 答复看来令人很满意。

Who can be depend upon to do such a job? 能靠谁来做这样的工作哪？
Before liberation, workers were made to work day and night. 解放前，工人们被迫日夜干活。

②在下列结构中用不等式作主语补足语，它们是：sb./sth be said/believed/reported/considered/found等+不等式。

如：
He is said to have gone abroad. (= It is said that he has gone abroad.)
Heat is considered to be a form of energy. 热被看成是一种能量。

③在be likely, be certain, be sure, be unlikely, be destined等加不等式的复合结构中，不等式也是用作主语的补足语。

Victory is sure to be ours. 胜利一定是属于我们的。

5、不定式作表语
不等式作表语时常用来表示预定要发生的动作，也可以用来表示未来的可能性或假设；
不等式作表语还可以用来说明主语的内容，此时不等式只是单纯的表语，而不具有未来的意义。

His wish is to become a scientist. 他的是当一名科学家。

To the doctor, the most important thing is to save people’s lives.对医生来说，最重要的是拯救生命。

Our main task now is to develop the students’ abilities to carry on independent work.培养学生进行独立的能力是我们现在的主要任务。

He was to leave when I walked into the room. 我走进房间时，他正想离开。

What we have to do first is to find a solution. 我们要做的第一件事找一个解决的办法。

The important thing is to win at any cost. 重要的是不惜一切代价取得胜利。

Nothing in life is to be feared. It is only to be understood.
生活中没有可怕的东西，只有需要理解的东西。

[摘自高二英语上P1]
Perhaps the most important thing if we want to make a difference is to find something that we like to do and that we are good at. 如果我们想有所成就，最重要的或许就是找到我们喜欢做的和擅长做的事情。

[摘自高二英语上P7]
6、不定式作定语和同位语
不等式作定语或同位语须放在被修饰词的后面.
He was very busy and had no time to visit his friends. 他很忙，根本没有时间看望朋友们。

The farmers thought of the ways to protect their crops. 农民们想出了保护庄稼的方法。

No investigation, no right to speak.没有调查就没有发言权。

They had no chance to go to school in those years. 那时候他们没有机会上学。

Her desire to succeed let her study hard. 对成功的渴望促使她努力学习。

Have you got anything to do this evening? 今晚你有事吗？
不定式作定语或同位语时应注意两种现象：
1、如果不等式是一个不及物动词，它后面就应带有必要的介词，但是修饰的名词是time、place、way时，其后习惯上常省略介词。

I have a lot of things to do.我有许多工作要做。

Let’s first find a room to find to put the things in.我们先找一个房间把东西搁在里面。

She is a very nice person to work with. 她是一个很好共事的人。

I haven’t got a chair to sit on. 我没有可坐的椅子。

There is nothing to worry about. 没什么值得发愁的。

I have never seen a zoo that was suitable for animals to live in. [摘自《Go for it》Ⅲ P120]
There is no reason to give up. 没有理由放弃。

This is the best way to make friends (with). 这就是最好的交朋友的最好方法。

We are looking for a place to lie (in).我们在找躺的地方。

She had no place to live. 她没地方住。

We have only a short time to decide.我们只有很少的时间来决定。

Zoos are terrible places for animals to live. (省略in) [摘自《Go for it》Ⅲ P120]
Is this a good way for animals to live? (省略in) [摘自《Go for it》Ⅲ P120]
2、不等式和它所修饰的词之间有主谓关系，且此不等式短语相当于一个定语从句。

We need someone to help him with the typing. 我们需要一个人帮他打字。

We need someone （who will help him with the typing,）
The meeting to take place next month is bound to be a great success. 下月举行的会议一定会很成功。

The meeting (which will take place next month) is bound to be a great success.
She is always the first to come to school. 她总是第一个到校。

7、不定式作状语
不定式作状语修饰动词，表示目的、原因、结果、独立成分等。

表示结果、原因时，不可置于句首。

1、不等式表示目的，其逻辑主语通常亦是全句的主语。

有时为了强调这种目的，在不等式前加in order或so as，也可以将不等式或“in order+不等式”置于句首（so as不用于句首）
The Greens went to Hong Kong to spend their holiday. 格林全家去香港度假了。

Let’s hurry not to be late for class. 咱们快点走，免得上课迟到。

To make things easier, some people would rather just give money.为了让事情简单些，一些人宁愿只送钱。

[摘自《Go for it》Ⅲ P108] We went to the village to buy some food from the village shop. 我们到那个村庄，从商店里购买了一些食物。

I’ll write down his telephone number in order to call him when necessary.我要把他的电话号码记下来，已备必要时打电话给他。

I stayed there so as to see what would happen. 我留在那儿，为的是想看看会发生什么事。

To do a good job, we must have the right ways. 要做好工作，我们要有正确的方法。

In order to help him, we would do everything we can. 为了帮助他，我们愿意尽一切力量。

In order not to be late, we took a taxi instead of a bus. 为了不迟到，我们没有乘公交车，而是打的。

To master a foreign language, one must study hard. 要掌握一门外语，就必须努力学习。

We do that so as to save time. 我们那样做是为了节省时间。

She shut the window in order to keep the rain out. 她关上窗户，把雨挡在外面。

In order to get married, I needed a job, and in order to get a job, I needed a Ph D.
为了结婚，我需要一份工作；为了找到工作，我需要哲学博士学位。

[摘自高二英语上P3]
To explain what they have seen, they build a theory about the way in which things happen and the causes and effects.
为了解释他们的观察所得，它们会建立一个关于事物发生、起因和结果的理论。

[摘自高二英语上P4]
2、不等式表原因，常用在表示喜、怒、哀、乐等情感形容词后面。

其逻辑主语通常是句子的主语。

如：
I’m glad to meet you.见到你我很高兴。

I’m sorry to hear that. 听到这个消息我很难过。

We jumped with joy to hear the news.听到这个消息，我们都高兴得跳了起来。

We are proud to be young people of China. 作为中国的青年，我们感到自豪。

She trembled to think of the terrible accident. 想到那可怕的车祸,她就不寒而栗。

She seemed surprised to meet us.见到我们，她看上去很惊讶。

I’m sorry to have kept you waiting. 不好意思，让你久等了。

3、不等式表结果，其逻辑主语通常也是句子的主语。

在“so…as to…”, “such…as to…”, “enough…to…”, “only to…”, 以及“too…to…”等结构中的不等式皆表示结果。

He was too exited to keep still.他太兴奋，无法保持平静。

I don’t know him well enough to borrow money from him. 我跟他还没有熟到可以向他借钱的地步。

What have I said to make you so sad? 我说了什么话是你如此伤心?
She was not old enough to understand all that. 她年纪不够大，无法理解这一切。

The smoke from the fire was too thick for the helicopters to be able to land on the roof. 大火产生的浓烟使直升机不能在屋顶降落。

He lifted a rock only to drop it on his own feet. 他搬起石头却砸了自己的脚。

He grew up to be a famous scholar. 他长大后成了著名的学者。

She woke up suddenly to see the house on fire.她突然醒来，发现房子着火了。

You are old enough to take care of yourself now. 现在你已经长了，能够照顾自己了。

It is too late to do anything now.现在做什么事都太晚了。

We were lucky enough to catch the last bus. 我们幸运地搭上了末班车。

He worked hard so as to pass the exam.他学习努力以便通过考试。

The test questions are kept secret, so as to prevent cheating. 试题保密是为了防止作弊。

Who can be so mean as to do such a thing like that? 谁这么小气，做出这样的事？
I went about my job in such a way as to kill two birds with one stone. 我如此工作是为了想要一箭双雕。

[go about:着手；从事 kill two birds with one stone：一箭双雕]
4、做独立成分。

这种不等式独立于句子之外，表示说话者的态度、语气等，又称评论性状语。

通常置于句首，有时置于句中或句尾，需要用逗号同句子的其他成分隔开。

To tell the truth, I don’t know what the answer is. 老实说，我不知道答案是什么。

To be honest, I thought the purse was really ugly! 说实在的，我认为那个钱包实在难看。

[摘自《Go for it》Ⅲ P108] Today’s writers should turn a real life into a piece of literature, to be frank.坦白地说，现在的作家应该将真实的生活写成文学。

常见作独立成分的不等式还有：
to speak frankly 坦率地说 to be honest 诚实说 to tell (you) the truth 说实话
to be frank 坦率地说 to begin with 首先 to start with 首先 to put it briefly 简言之
三、“疑问词+不定式”结构
不等式短语在某些情况下可以在前面带一个疑问词（连接代词/副词）。

[why除外]这种结构的作用接近于一个名词从句，在句中用作主语、表语、宾语或介词宾语。

When to start hasn’t been decided yet. 何时动身尚未决定。

[作主语]
The question is where to go. 问题是到哪儿去。

[作表语]
Life is long if you know how to live it. 若知如何利用，生命就能长久。

[作宾语]
I was thinking of how to tell him the truth. 我正在想要怎么告诉她这个事实。

[作介词的宾语]
Do you know how to write a letter in English? 你知道如何用英语写信吗？[作宾语]
They want to have a vacation, but they haven’t decided where to go. 他们想去度假，但还没有决定去哪儿。

[作宾语] He told the actors where to stand and where to move.他告诉演员们该站在哪儿，该往哪儿走。

I don’t know which to choose because there isn’t any difference between the two.因为这两者之间毫无区别，所以我这不知道该选哪一个。

We must decide whether to go or stay. 我们必须决定是去还是留。

I so hope you’ll advise me what to do. 我真希望你会建议我该怎么办？
The teacher will teach us how to learn English well. 老师会教我们如何才能学好英语。

四、省略t o的不定式
to是动词不定式常常带有的小品词，是不等式的标志。

但在下列情况下它常常被省略掉。

1、在情态动词之后
Can I have a look at your new computer? 我能看看你的新电脑吗？
May I take this seat?我可以坐在这里吗？
2、在had better, had best, why（not），would rather, would rather…than…, would sooner, would sooner…than…, do nothing but, cannot but, cannot help but等等后面的不等式要省略to。

You’d better look over your paper before you hand it in. 交卷前你最好仔细检查一下。

You’d better not ask such silly questions again. 你最好不要再问这样愚蠢的问题。

Why leave the light on? 为什么开着灯？
Why stand here in the cold? 这么冷，站在这里干什么？
I would rather stay at home. 我宁愿呆在家里。

We would rather fail than do nothing at all. 我们宁愿失败也不愿无所事事。

I would sooner take a taxi than walk. 我宁愿坐出租车而不是走着去。

The students could do nothing but wait for the teacher to come. 学生们没有别的方法，只好等老师来。

Why spend so much money? 为什么要花这么多钱？
Why not have a try? 为什么不试一试呢？
I cannot but think so. 我很难不这样想。

I cannot help but agree to what he said. 我不得不同意他所说的。

3、在某些感官动词后的宾语补足语之前。

这些感官动词有：see、watch、hear、feel、listen to、notice、look at等。

I didn’t notice her go out. 我没注意她出去了。

Did you hear him go downstairs? 你没有听到他下楼的声音吗？
4、在某些使役动词后的宾语补足语之前。

这些使役动词有：make、have、 let.
She let us meet her at the station. 她让我们去车站接她。

What makes you think so? 什么使得你这么认为？
Don’t make him cry. 别让他哭啦。

She made me promise to write every day. 她让我每天写。

The teacher often has the students read aloud every day. 这位老师经常让学生们在课堂上大声朗读。

5、有but、except用作介词（除……之外）接不等式，如前面有do/does/did时，不等式不带to，否则要带to.
The lady can do nothing but give in. = The lady has no choice but to give in.
6、几个不等式并列时，常常只在第一个动词前加to，在后面的不等式则不加to.
It’s kind of you to come and see me. 你来看我真是太好了。

I decided to write rather than phone. 我宁愿写信而不打电话。

It is quite necessary for us to write more and read more. 我们多写多说是十分必要的。

She told the children to stay there and wait till she came back. 他叫孩子一直呆在那里一直等他回来。

★注意：如果表示对比或强调，每一个不等式的to都要保留。

I came to praise him, (but) not to blame him. 我是来表扬他，而不是责备他。

To try and fail is better than to do nothing at all. 尝试后而失败总比无所事事要好。

He hasn’t decided whether to go home or to stay here. 他还没决定是回家还是留在这里。

7、不等式作表语时，主语部分有实义动词do的某种形式，to也可以省略。

（美语中常见）
All we can do now is (to) wait for him. 现在我们能做的就是等他。

What we must do is (to) reduce the use of energy. 我们不需做的就是减少能源的消耗。

8、在help后面的宾语补足语可带to也可不带to. ★变为被动语态时，则须带to.
She helps her mother (to) prepare for Christmas.她帮她妈妈为圣诞节做准备。

Her mother is helped to prepare for Christmas.
五、t o后面动词的省略
1、有时为了避免重复前面的动词，可以把一个动词不等式省略掉，单留一个“to”。

一般说来在一些形容词、动词后面的不等式内容如果是重复前面内容时，to后的动词可承前省略，此时所省略的成分相当于do so，这种结构一定要有上下文或一定的语境。

常见的这类动词有：；like, love, hope, wish, want, mean, try, intend, oblige, advise, refuse, persuade等；形容词有：happy, glad, eager, anxious, ready, willing等。

He may stay if he wants to. 如果他想留下来，他就可以留下来。

--- Will you go together with me? --- Does she intend to study German?
--- Yes, I will be glad to. --- Yes, she intends to.
I’d like to go skating on such a snowy day, but my mom asked me not to.
我想在这样的下雪天去滑冰，但妈妈叫我别去。

[省略go skating]
★如果在省略的不等式结构中含有作助动词的be, have, have been, to后面要保留这些词。

--- Are you on holiday? --- No, but I’d like to be.
--- I thought you were a teacher. --- No，but I used to be.
--- Didn’t she tell you to attend the meeting? --- 她没有告诉你参加会议吗？
--- No, I ought to have been. [省略了told] --- 没有，我应该被告知的。

2、某些固定结构后面常省略不等式而保留to.常见的有：ought to, have to, used to, be able to等。

His aunt won’t attend the wedding though she ought to.虽然她姑姑应该参加婚礼，但她不打算去。

[省略了attend the wedding]
Harry has succeeded in the final exam, and in fact, he ought to have.
哈里通过了期末考试，而实际上，它也是应该通过的。

[省略了succeeded]
--- I didn’t tell him the news. --- Oh, you ought to have.
六、不定式的时态
不定式虽然没有人称和数的变化，但所表达的动作仍有时间先后顺序。

1、不定式的一般式，表示的动作通常与谓语动词表示的动作同时发生或在其后发生。

We are very glad to meet you again.再次见到你，我们非常高兴。

（同时发生）
I hope to see you next week. 我希望下周能见到你。

[不等式动作发生在谓语之后]
They invited us to visit the United States soon.他们邀请我们不就去美国访问。

2、不定式的进行式，表示的动作正在进行，与谓语动词表示的动作同时发生。

He seems to be thinking deeply, without noticing me passing him. 他似乎陷入了沉思，我从他身边经过他都没注意到。

It’s nice of you to be thinking of us. 谢谢你想着我们。

（作主语）
They are to be waiting for us at the station. 他们在车站等我们。

（作表语）
He pretended to be reading attentively when I came in. 我进去时他假装在专心读书。

（作宾语）
3、不定式的完成式，表示的动作发生在谓语表示的动作之前。

I am sorry to have given you so much trouble.真对不起，给你带来这么多麻烦。

He pretended not to have seen me. 他假装没有看见我。

He is the first student in the school to have got the prize. 在该校，它是第一个获得该奖的学生。

There is no need to have worried about it like that. 不需要那样担忧。

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

4、如果不定式表示的不是正在进行的动作，而是在谓语所表示时间之前一直进行的动作，就要用完成进行式。

She wished to have been reading as much as the others. 她真希望过去也想其他人那样看那么多的书。

She is said to have been writing the novel about New York for years. 据说多年来他一直在写这本关于纽约的小说。

We wished you both to have been getting along quite well. 我们希望你们俩儿一直相处甚好。

七、不定式的语态
比较两种形式在意义上是有区别的。

I am ready to shave. 我要刮脸了。

（自己挂自己的脸）
I am ready to be shaved. 我准备好刮脸了。

（由别人给自己刮脸）
1、当不等式的逻辑主语是这个不等式所表示动作的承受者时，一般要用被动形式。

The car needs to be repaired before we go on a trip to Europe. 在我们去欧洲之前，这辆车需要修理一下。

The class meeting is to be held tomorrow. 明天举行班会。

The problem remains to be solved. 这问题还有待解决。

The room seems to have been tidied up already. 这个房子似乎好像已经整理过了。

She was too young to be given such work. 她年纪太小，不宜把工作交给她去做。

He went to the hospital to be examined. 她去医院检查身体去了。

The books are not allowed to be taken out of the reading room. 书不需拿出如阅览室。

He wanted the homework to be handed in at once. 他要求把作业马上交上去。

2、不等式的以主动形式表示被动意义的情况常见有以下几种：
①当不等式修饰的名词和不等式构成主谓关系时。

Do you have a knife to cut the watermelon? (A knife cuts the watermelon.)
We have a lot of things to do. 我们有很多事要做。

Give him something to eat. 给他一点吃的东西。

Have you got anything to say?你有什么要说的吗？
If you want to make even greater progress in your studies, you still have many difficulties to overcome.
②在“be+性质形容词+不等式”结构中。

He is not easy to get along with.他不宜相处。

This kind of fish is nice to eat.
The water is not fit to drink. 这水不能喝。

This book is difficult to understand.
常见的这类形容词有：easy, hard, difficult, interesting, heavy, pleasant, comfortable, safe, impossible等。

③在“疑问词+不等式”结构中，主动表被动。

What to do next hasn’t been decided. 下一步做什么还没决定。

In society, I don’t know who to compare fairly with. 在社会上，我不知道和谁公平竞争。

④某些动词不等式与be连用时，主动表被动。

这类动词常见的有to blame(责怪)、to seek(寻找)、to let（出租）
This house is to let. 此房出租。

The causes of the 11·3 fire are not far to seek. 11·3大火的根源不难找。

I felt I was to blame for that mistake. 我觉得那个错误应该怪我。

3、在“there be……”结构中，用来修饰主语的不等式可以用被动形式，在口语中也可以用主动形式。

There is no time to lose.(to be lost) 时间不能耽搁了。

八、考点与难点解析
1、of和for的区别，即句型It is + adj.+ of sb. to do.与It is + adj.+ for sb. to do.的区别。