To tell the truth, I don’t agree with you.
8）不定式与疑问词who，which，when，where，how，what等连用，在句中起名词作用，可充当主语、表语、宾语等。如：
He didn’t know what to say. （宾语）
How to solve the problem is very important. （主语）
注意：在与why连用时，只用于why或why not开头的简短疑问句中，后面紧跟的动词不定式不带to。例如：
Why not have a rest ?
9）不定式在句中用主动式还是被动式，多数情况下是容易判断的，但有时的确比较复杂，请注意以下几点：
①不定式修饰的名词或代词和不定式逻辑上构成主谓关系时，不定式往往用主动形式。如：
Have you got a key to unlock the door ?
(A key unlocks the door. )
②不定式和它前面被修饰的名词或代词构成逻辑上的动宾关系，又和该句主语构成逻辑上的主谓关系时，不定式常用主动形式。
I have got a letter to write. （I write letter. ）
He needs a room to live in. （He lives in a room. ）
I know what to do. （I do what. ）
但这句如改为下列形式，不定式就得用被动形式：I know what is to be done.
这是因为what is to be done是宾语从句，从句中的主语what是动词do的动作对象。
③不定式作表语形容词的状语，和句中主语构成逻辑上的动宾关系时，不定式多用主动形式，这是因为人们往往认为形容词后省去了for sb. 。如：
He is hard to talk to. （to talk to him）
The book is difficult to understand. （to understand the book）
④在there be结构中，当说话人考虑的是必须有人去完成某件事时，不定式用主动形式；如果说话人强调的事情本身必须完成，则用被动形式。
There is a lot of work to do. （Somebody has to do the work. ）
There is a lot of work to be done. （The work has to be done. ）
请注意下面两个句子的含义是不同的：
There is nothing to do. （无事可做，感到十分乏味。）
There is nothing to be done. （某东西坏了，无法使之恢复正常。）
2．不定式的时态
1）不定式的一般形式所表示的动作，通常与谓语的动作（状态）同时（或几乎同时）发生，或是在它之后发生。例如：
I saw him go out.
2）如果谓语表示的动作（情况）发生时，不定式表示的动作正在进行，这时不定式就要用进行式。例如：
He pretended to be reading a book when she went in.
3）如果不定式的动作发生在谓语动词之前，就要用完成式。例如：
I’m sorry to have kept you waiting.
3．不定式的语态
当不定式逻辑上的主语是这个不定式所表示的动作的承受者时，不定式一般要用被动形式。如：
He asked to be sent to work in the countryside.
It is possible for our hopes to be realized.
4．不定式符号to的保留问题
有时为了避免重复，可以用to来代替前面的不定式，这种情况常出现下列动词后：expect，prefer，care，mean，forget，want，wish，hope，try以及be glad/happy等后。
如果在省略的不定式结构中含有be，have，have been，这些词要保留。如：
—Are you on holidays ?
—No, but I’d like to be.
—I didn’t tell him the news.
—Oh, you ought to have
动词不定式、动名词用法要点讲解详细内容
⒈不定式作主语
动词不定式作主语时，句子的谓语动词常用单数，其位置有以下两种： (1)把不定式置于句首。如：
To get there by bike will take us half an hour.
(2)用it作形式主语，把真正的主语不定式置于句后，常用于下列句式中。如： ①It＋be＋名词＋to do
It's our duty to take good care of the old. ②It takes sb+some time+to do
How long did it take you to finish the work? ③It＋be＋形容词＋for sb＋to do
It is difficult for us to finish writing the compositionin a quarter of an hour. ④It＋be＋形容词＋of sb＋to do
It is stupid of you to write down everything the teachersays. ⑤It seems(appears)＋形容词＋to do It seemed impossible to save money.
在句型③中，常用表示客观情况的形容词，如：difficult,easy,hard,important,impossible,necessary 等；在句型④中，常用careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise等 表示赞扬或批评的词。在不定式前的sb，可看作其逻辑主语。这一句式有时相当于Sb is＋形容词＋to do句式 ，如：It'skind of you to help me with my English.=You are kind to helpme with my English. ⒉动名词作主语
Learning without practice is no good. 动名词作主语时，也常用It句式。如：
①It's +no good(no use,fun,a pleasure,a waste of time)+doing… It's no good reading in dim light. It's no use sitting here waiting. ②It's＋形容词＋doing
It's dangerous swimming in the sea in windy days.
这样用的形容词有expensive,nice,tiring等，但important,necessary则不适用于这种结构，应用不定式 代
替，如：It'simportant for you to keep fit. ③There is no+doing
There is no saying what will happen next.
在这一结构中，动名词后常带宾语，相当于\结构。 ⒊动词不定式和动名词作主语的区别
①不定式作主语经常表示具体动作，常与特定的动作执行者联系在一起；而动名词作主语经常表示抽象动 作，经常不与特定的动作执行者联系在一起。如： It's no good eating too much fat. It's no good for you to eat so much fat.
②动名词结构作主语，可以用名词或代词属格形式作逻辑主语。如： It's no use your pretending that you didn't know the rules. 二、作宾语 ⒈不定式作宾语
①
以
下
动
词
后
，
只
能
跟
不
定
式
作
宾
语
。
如
：
agree,ask,aim,arrange,choose,decide,demand,expect,fail ,help,hope,lean,long,
manage,offer,plan,prepare,pretend,promise,refuse,wish等，这些词大部分可接th at引导的从句。如： I decided to ask for my money back.
I decided that I would ask for my money back.
When our visit to the farm was over,we expected to startback on foot.
When our visit to the farm was over, we expected that wewould start back on foot.
②当复合宾语中的宾语是不定式时，先用形式宾语it代替不定式，把不定式置于补语之后，即：主语＋动 词＋it＋补语＋to do句式。如：
We think it quite important for us to learn a foreignlanguage well. He feels it his duty to help the poor. ③介词but,except,besides+to do(do)
在这种句型中，如介词前有动词do，后面应接不带to的不定式；如无do，则接to不定式，即带do不带to， 带to不带do。如：
The enemy soldiers had no choice but to give in. On Sunday afternoon I had nothing to do but watch TV. ⒉动名词作宾语
①以下动词后，只能接动名词作宾语，如：admit,appreciate,consider,delay,enjoy,finish,keep,imag ine,mind,miss,practise,resist,risk,save,suggest,don't mind,give up,insist,on, put off等。如： I suggest spending our summer vacation in a seaside town. You must give up smoking, for it does too much harm toyour health. ②动名词作介词的宾语
I should go to attend the birthday celebration instead of staying at home. What about inviting Li Jun to make a speech?
动名词前的介词有时可以省略，如：have difficulty(in)doing,have no trouble(in)doing,lose no ti me(in)doing,prevent/stop…(from)doing,there is no use(in)doing等。
⒊部分动词后面，既可接动词不定式，也可接动名词作宾语，意义不变。如：begin,continue,start,hat e,like,love,need,require,want等。
在need,require,want后接-ing形式，表示被动意义，也可接不定式，但要用被动形式，如：Your handwr iting needs improving(tobe improved). hate,love,like接不定式表示特定的未来事件，接动名词表示目前 正在进行的活动或一般的行为。
在下列情况下，一般要用不定式：
①hate,like,love前有would(should)时，如：I'd like to have a cup of coffee.
②当谓语动词begin,continue,start等是进行式时，如：Thestudents are starting to work on the di fficult maths problem.
③begin,continue,start与know,understand等状态动词连用时，如：I soon began to understand what was happening.
⒋advise,allow,encourage,forbid,permit等动词后接动名词作宾语，或带不定式作宾语补足语。如： Our teachers don't permit our swimming in the lake. Our teachers don't permit us to swim in the lake.
⒌部分动词后接不定式或动名词时，意义差别较大，应根据句子语境选择使用。
①forget,remember,regret后接不定式，表示现在或未来的动作，接动名词表示动作已经发生。如： Don't forget fo post the letter for me.
Have you forgotten meeting her in Beijing Airport? Remember to close the windows before you leave. I remember writing him a letter a year ago.
We regret to tell you that all of you are not invited toattend the meeting. They regretted ordering these books from abroad. ②mean to do 打算做某事 doing 意味着……
I meant to catch up with the early bus. This means wasting a lot of money. ③try to do 设法尽力做某事 doing 试着做某事
You should try to overcome your shortcomings. Try working out the physics problem in another way.
④stop to do 停下一件事去做另一件事（不定式作目的状语） doing 停止做某事
On the way to the airport,I stopped to buy a paper. You'd better stop arguing and do as you are told. ⑤can't help doing 禁不住…… to do不能帮助干……
They couldn't help jumping up at the news.
Sorry I have lots of work to do.So I can't help to make up the room for you. ⑥go on to do 做不同的事或不同内容的事 doing 继续不停地做某事，指同一动作的继续
He went on to talk about world situation.他接着又谈了世界形势。 We'll go on fighting so long as there is oppression inthe world. ⑦leave off to do 离开某地去干什么（目的状语） doing停下某事
It's time to leave off talking and to start acting. They left off to go fishing. 三、做表语
不定式作表语表示具体动作或将来动作；动名词作表语表示抽象的一般行为。 ①To be kind to the enemy is to be cruel to the people.