不定式
不定式通常由不定式符号to+动词原形构成，但在某些搭配中不带to 。不带to 的不定式便与动词原形同形。
不定式形式
1、常见的形式如表所示（以及物动词do 为例），不及物动词没有被动语态。
的不定式形式，如：You had better say nothing．
3、 为了避免重复，有时不定式的to 可代替整个
不定式：---Do you smoke？ ---No ，but I used to（smoke ）．
不定式用法
1 有些动词可以用不定式作宾语，大致上有三种情况。
1）有些及物动词用不定式作宾语，结构为动词+不定式。
例如：afford aim agree arrange ask decide bother care choose demand desire determine elect endeavor hope fail help learn long mean manage offer plan pretend refuse tend undertake expect hate intend 例如：
The driver failed to see the other car in time.
He offered to help me.
2）有些动词除了可以用不定式作宾语，还用不定式作补语，即有动词+宾语+不定式的结构。如：ask choose expect help begin tend like love need prefer prepare want wish I like to keep everything tidy. → I like you to keep everything tidy.
3）有些动词或动词词组可以用动词+疑问词+不定式的结构作宾语。例如：decide know consider forget learn remember show wonder find out tell inquire explain
Please show us how to do that.
There are so many kinds of recorders that I can't make up my mind which to buy.
2、不定式作补语
1）动词+宾语+不定式（to do）的结构。如：
advise allow appoint believe cause challenge command compel consider declare drive enable encourage find forbid force guess hire imagine impel induce inform instruct invite judge know like order permit persuade remind report request require select send
state suppose tell think train trust understand urge warn Father will not allow us to play on the street.
The officer ordered his men to fire.
注意
有些动词如make ，have ，get ，want, 等可用不定式作宾补，也可用分词作宾补。现在分词表达主动，也表达正在进行，过去分词表达被动。
2) 动词+宾语+不定式（to be）如
Acknowledge, believe, consider, think, declare(声称), discover, fancy(设想), feel find, guess, judge, imagine, know, prove, see(理解), show, suppose, take(以为), understand
e.g. We consider Tom to be one of the best students in our class.
[注] 宾语补语to be在believe ，consider ，declare ，find ，prove ，think ，imagine 等之后常可省去，如：
①We believe her innocent.
②I consider him too lazy.
在上述动词的被动结构中，后面的to be亦可省去：
③She was believed innocent.
④He was considered too lazy.
有些动词可以跟there +to be的结构。例如：
believe expect intend like love mean prefer want wish understand
e.g. We didn't expect there to be so many people there.
You wouldn‟t want there to be another war.
3、 不定式作主语
不定式作主语，往往用it 作形式主语，真正的主语不定式放至句子的后面。例如：
It's so nice to hear your voice. 听到你的声音真高兴。
It's necessary for you to lock the car when you do not use it. 不用车的时候，锁车是有必要的。
It's very kind of you to help us. 他帮助我们，他真好。
It seemed selfish of him not to give them anything. 他不给他们任何东西，这显得太自私了。 但是，用不定式作主语的句子中还有一个不定式作表语时，不能用It is… to…的句型。另外，这样的句子，不能用动名词作表语。
（ 对）To teach is to learn.（错 ）It is to learn to teach.
（ 错）To teach is learning.（ 错）Teaching is to learn.
典型例题：
The chair looks rather hard, but in fact it is very comfortable to ___.
A. sit B. sit on C. be seat D. be sat on （B ）
注意：如果不定式为不及物动词，其后应有必要的介词。当动词与介词连用时，介词常位于“形容词+动词不定式‟‟结构的末尾。
4 、It 's… for sb. to do sth. 和 It's …of sb. to do sth.
for 或of 的区别。
1）for sb. 句型中的形容词一般为表示事物的特征特点，表示客观形式的形容词，如easy, hard, difficult, interesting, impossible等，例如：It„s very hard for him to study two languages. 对他来说学两门外语是很难的。
2）of sb. 句型中的形容词一般为表示性格，品德，心智能力，表示主观感情或态度的形容词，如good, kind, nice, clever, foolish, right等。例如：It„s very nice of you to help me. 你来帮助我，真是太好了。
注意：用for 还是用of 的另一种辨别方法：
用介词for 或of 后面的逻辑主语作句子
的主语，再用介词前边的形容词作表语，造个句子。如果通顺就用of ，不通则用for 。如在下面两个句子中：
① It„s very hard for him to study two languages.
② It„s very nice of you to help me.
句①中 He is hard.非所表达的意思，不通，因此用for 。
句②中 You are nice. 通顺，所以应用of 。
5 、不定式作表语
不定式可放在be 动词后面，形成表语。例如：
My work is to clean the room every day. 我的工作是每天清扫房间。
His dream is to be a doctor. 他的梦想是成为一名医生。
6、 不定式作定语
不定式做定语通常要放在被修饰的词后，往往表示未发生的动作。例如：
I have a lot of work to do. 我有许多事要做。
There was nothing to bring home that morning. 那天早上（他回家时）两手空空。
7、 不定式作状语
1）目的状语
常用结构为to do , only to do（仅仅为了）, in order to do, so as to do, so （such ）… as to…（如此…以便…）。例如：
He ran so fast as to catch the first bus. 他飞快地跑以便赶上第一班车。
I come here only to say good-bye to you. 我来仅仅是向你告别。
2）作结果状语，可以表示没有预料到的或事与愿违的结果，不定式要放在句子后面。 I awoke to find my truck gone. 我醒来发现我的搬行李的手推车不见了。
He searched the room only to find nothing. 他搜索了房间，没发现什么。
3） 表原因
I'm glad to see you. 见到你很高兴。
She wept to see the sight. 她一看到这情形就哭了。
4）表示理由和条件
He must be a fool to say so.
You will do well to speak more carefully.
8、用作介词的to
to 可以用作介词，也可用作不定式的标示。下面的to 都用作介词：
admit to object to be accustomed to be used to stick to turn to（开始） look forward to be devoted to pay attention to contribute to apologize to devote oneself to
9、 省去to 的动词不定式
1） 情态动词 （ 除ought 外） 后。
2） 使役动词 let, have, make后，感官动词 see, watch, look at, notice , observe, hear, listen to, smell, feel, find 等后。
注意：被动语态中不能省去to 。例如： I saw him dance. =He was seen to dance.
The boss made them work the whole night. =They were made to work the whole night.
3） would rather，had better句型后
4） Why… / why not…句型后
5） help 后可带to ，也可不带to, help sb （to ） do sth.
6） but 和except 后。but 前是实义动词do 时，后面出现的不定式不带to 。
比较：He wants to do nothing but go out. 他只想出去玩。
He wants to believe anything but to take the medicine. 除了吃这药，他什么都信。
7） 由and, or和than 连接的两个不定式，第二个to
可以省去：
8） 通常在discover, imagine, suppose, think等词后作主补时，可以省去to be。例如： He is supposed （to be） nice. 他应该是个好人。
典型例题
1） ---- I usually go there by train.
---- Why not ___ by boat for a change?
A. to try going B. trying to go
C. to try and go D. try going （D ）
2） Paul doesn't have to be made ___. He always works hard.
A. learn B. to learn C. learned D. Learning （B ）
10、动词不定式的否定式
在不定式标志to 前加上not 。例如：
Tell him not to shut the window。
She pretended not to see me when I passed by.
典型例题
1）Mrs. Smith warned her daughter ___ after drinking.
A. never to drive B. to never driver
C. never driving D. never drive （A ）
2） The boy wanted to ride his bicycle in the street，
but his mother told him ____.
A. not to B. not to do
C. not do it D. do not to （A ）
说明：not to 为not to do it 的省略形式。
不定式的特殊句型
1、不定式的特殊句型too+形容词／副词+不定式 ：“太…以至于不能…”。
1）例如：He is too excited to speak. 他太激动了，说不出话来。
She works too slowly to be much use to me．
她干活太慢，对我不会有多大帮助。
Well, I'm afraid the box is too heavy for you to carry it, but thank you all the same.
不用了。这箱子太重，恐怕你搬不动。谢谢。
2） 如在too 前有否定词，则整个句子用否定词表达肯定，too 后那个词表达一种委婉含义，意 为" 不太" 。例如： It's never too late to mend.改过不嫌（谚语）
3） 当too 前面有only, all, but时，意思是：非常… 等于very 。例如：I'm only too pleased to be able to help you. 能帮助你我非常高兴。He was but too eager to get home. 他非常想回家。
2、不定式的特殊句型so as to
1） 表示目的；它的否定式是 so as not to do。例如：
T om kept quiet about the accident so as not to lose his job.汤姆对事故保持沉默是为了不丢掉他的工作。
Go in quietly so as not to wake the baby.轻点进去，别惊醒了婴儿。
2）表示结果。例如：
Would you be so kind as to tell me the time? 劳驾，现在几点了。
3、不定式的特殊句型Why not
"Why not +动词原形" 表达向某人提出建议，翻译为：" 为什么不……?" "干吗不……?"。例如： Why not take a holiday? 干吗不去度假?
4、不定式的特殊句型形容词／副词+enough +不定式
（a ）如在too 结构中一样，不定式可以指动词的主语而言：
She is old enough to travel by herself．
He didn‟t jump high enough to win a prize．
（b ）这种结构还可以指动词的宾语而言：
After a few minutes the coffee was cool enough（for us） to drink．(…the coffee was so cool that we can drink it)
He spoke slowly enough for everyone to understand．
（c ）这种结构也可以指介词的宾语而言：
The ice was thick enough to walk on．不定式时态和语态
1） 一般式表示的动词，有时与谓语动词表示的动作同时发生，有时发生在谓语动词的动作之
后，例如： He seems to know this. 他似乎知道这事。
I hope to see you again. = I hope that I'll see you again. 我希望再见到你。
2） 完成式表示的动作发生在谓语动词表示的动作之前。例如：
I'm sorry to have given you so much trouble. 很抱歉，给你添了那么多的麻烦。
He seems to have caught a cold. 他好像已经得了感冒。
3） 进行式表示动作正在进行，与谓语动词表示的动作同时发生。例如：
He seems to be eating something. 他好像正在吃什么东西。
4） 完成进行式表示动作从过去开始并延续至说话的时候。例如：
She is known to have been working on the problem for many years. 我们知道她研究 这问题有好几年了。
动名词与不定式 ：
1、1）动名词与不定式的区别：
动名词表达的是： 状态，性质，心境，抽象，经常性，已发生的
不定式表达的是： 目的，结果，原因，具体，一次性，将发生的
2）有些动词后面跟不定式或动名词作宾语，意义基本相同。
3）有些动词后面跟不定式或动名词作宾语，意义大相径庭。
2、特殊词精讲：
1） stop doing/to do
stop to do 停止，中断做某事后去做另一件事，stop doing 停止做某事。例如：
They stop to smoke a cigarette. 他们停下来，抽了根烟。
I must stop smoking. 我必须戒烟了。
2） forget doing/to do
forget to do 忘记要去做某事，forget doing 忘记做过某事。例如：
The light in the office is still on. He forgot to turn it off. 办公室的灯还在亮着，他忘记关了。（没有做关灯的动作）
He forgot turning the light off. 他忘记他已经关了灯了。（已做过关灯的动作）
3) remember doing/to do
remember to do 记得去做某事，remember doing 记得做过某事。例如：
Remember to go to the post office after school. 记着放学后去趟邮局。
Don't you remember seeing the man before? 你不记得以前见过那个人吗?
4） regret doing/to do
regret to do 对将要做的事遗憾，regret doing 对做过的事遗憾、后悔。例如：
I regret to have to do this, but I have no choice. 我很遗憾必须这样去做，我实在没有办法。 I don„t regret telling her what I thought. 我不为告诉她我的想法而后悔。
5） cease doing/to do
cease to do 长时间，甚至永远停做某事，cease doing 短时停止做某事，以后还会接着做。例如：
That department has ceased to exist forever. 那个系已不复存在。
The girls ceased chatting for a moment when their teacher passed by. 姑娘们在老师走过时，停了会聊天。
6） try doing/to do
try to do 努力，企图做某事，try doing 试验，试着做某事。例如：
You must try to be more careful. 你可要多加小心。
I tried gardening but didn„t succeed. 我试着种果木花卉，但未成功。
7） go on doing/to do
go on to do 做了一件事后，接着做另一件事，go on doing 继续做原来做的事。例如： After he had finished his maths，he went on to do his physics. 做完数学后，他接着去做物理。 Go on doing the other exercise after you have finished this one. 作完这个练习后，接着做其他的练习
8） be afraid to do ／of doing
be afraid to do 不敢，胆怯去做某事，是主观上的原因不去做，意为" 怕" ，be afraid of doing 担心出现doing 的状况、结果。doing 是客观上造成的，意为" 生怕，恐怕" 。例如：
She was afraid to step further in grass because she was afraid of being bitten by a snake. 她生怕被蛇咬着，不敢在草丛中再走一步。
9) be interested to do /in doing
interested to do 对做某事感兴趣，想了解某事，interested in doing 对某种想法感兴趣，doing 通常为想法。例如：
I shall be interested to know what happens. 我很想知道发生了什么事。（想了解）
I'm interested in working in Switzerland.
Do you have any idea about that?
我对在瑞士工作感兴趣。你想过这事吗? （一种想法）
10) mean doing/to do
mean to do 打算、想，mean doing 意味着。例如：I mean to go, but my father would not allow me to. 我想去，但是我父亲不肯让我去。T o raise wage means increasing purchasing power. 增加工资意味着增加购买力。
11) begin（start ） doing/to do
1） 谈及一项长期活动或开始一种习惯时，使用doing 。例如：
How old were you when you first started playing the piano? 你几岁时开始弹钢琴？
2） begin, start用进行体时，后面动词用不定式to do。例如：I was beginning to get angry。
我开始生起气来。
3） 在attempt, intend, begin, start 后接know, understand, realize这类动词时，常用不定式to do。
例如：I begin to understand the truth。我开始明白真相。
4） 事物作主语时。例如：The snow began to melt.雪开始融化了。
不定式
不定式通常由不定式符号to+动词原形构成，但在某些搭配中不带to 。不带to 的不定式便与动词原形同形。
不定式形式
1、常见的形式如表所示（以及物动词do 为例），不及物动词没有被动语态。
的不定式形式，如：You had better say nothing．
3、 为了避免重复，有时不定式的to 可代替整个
不定式：---Do you smoke？ ---No ，but I used to（smoke ）．
不定式用法
1 有些动词可以用不定式作宾语，大致上有三种情况。
1）有些及物动词用不定式作宾语，结构为动词+不定式。
例如：afford aim agree arrange ask decide bother care choose demand desire determine elect endeavor hope fail help learn long mean manage offer plan pretend refuse tend undertake expect hate intend 例如：
The driver failed to see the other car in time.
He offered to help me.
2）有些动词除了可以用不定式作宾语，还用不定式作补语，即有动词+宾语+不定式的结构。如：ask choose expect help begin tend like love need prefer prepare want wish I like to keep everything tidy. → I like you to keep everything tidy.
3）有些动词或动词词组可以用动词+疑问词+不定式的结构作宾语。例如：decide know consider forget learn remember show wonder find out tell inquire explain
Please show us how to do that.
There are so many kinds of recorders that I can't make up my mind which to buy.
2、不定式作补语
1）动词+宾语+不定式（to do）的结构。如：
advise allow appoint believe cause challenge command compel consider declare drive enable encourage find forbid force guess hire imagine impel induce inform instruct invite judge know like order permit persuade remind report request require select send
state suppose tell think train trust understand urge warn Father will not allow us to play on the street.
The officer ordered his men to fire.
注意
有些动词如make ，have ，get ，want, 等可用不定式作宾补，也可用分词作宾补。现在分词表达主动，也表达正在进行，过去分词表达被动。
2) 动词+宾语+不定式（to be）如
Acknowledge, believe, consider, think, declare(声称), discover, fancy(设想), feel find, guess, judge, imagine, know, prove, see(理解), show, suppose, take(以为), understand
e.g. We consider Tom to be one of the best students in our class.
[注] 宾语补语to be在believe ，consider ，declare ，find ，prove ，think ，imagine 等之后常可省去，如：
①We believe her innocent.
②I consider him too lazy.
在上述动词的被动结构中，后面的to be亦可省去：
③She was believed innocent.
④He was considered too lazy.
有些动词可以跟there +to be的结构。例如：
believe expect intend like love mean prefer want wish understand
e.g. We didn't expect there to be so many people there.
You wouldn‟t want there to be another war.
3、 不定式作主语
不定式作主语，往往用it 作形式主语，真正的主语不定式放至句子的后面。例如：
It's so nice to hear your voice. 听到你的声音真高兴。
It's necessary for you to lock the car when you do not use it. 不用车的时候，锁车是有必要的。
It's very kind of you to help us. 他帮助我们，他真好。
It seemed selfish of him not to give them anything. 他不给他们任何东西，这显得太自私了。 但是，用不定式作主语的句子中还有一个不定式作表语时，不能用It is… to…的句型。另外，这样的句子，不能用动名词作表语。
（ 对）To teach is to learn.（错 ）It is to learn to teach.
（ 错）To teach is learning.（ 错）Teaching is to learn.
典型例题：
The chair looks rather hard, but in fact it is very comfortable to ___.
A. sit B. sit on C. be seat D. be sat on （B ）
注意：如果不定式为不及物动词，其后应有必要的介词。当动词与介词连用时，介词常位于“形容词+动词不定式‟‟结构的末尾。
4 、It 's… for sb. to do sth. 和 It's …of sb. to do sth.
for 或of 的区别。
1）for sb. 句型中的形容词一般为表示事物的特征特点，表示客观形式的形容词，如easy, hard, difficult, interesting, impossible等，例如：It„s very hard for him to study two languages. 对他来说学两门外语是很难的。
2）of sb. 句型中的形容词一般为表示性格，品德，心智能力，表示主观感情或态度的形容词，如good, kind, nice, clever, foolish, right等。例如：It„s very nice of you to help me. 你来帮助我，真是太好了。
注意：用for 还是用of 的另一种辨别方法：
用介词for 或of 后面的逻辑主语作句子
的主语，再用介词前边的形容词作表语，造个句子。如果通顺就用of ，不通则用for 。如在下面两个句子中：
① It„s very hard for him to study two languages.
② It„s very nice of you to help me.
句①中 He is hard.非所表达的意思，不通，因此用for 。
句②中 You are nice. 通顺，所以应用of 。
5 、不定式作表语
不定式可放在be 动词后面，形成表语。例如：
My work is to clean the room every day. 我的工作是每天清扫房间。
His dream is to be a doctor. 他的梦想是成为一名医生。
6、 不定式作定语
不定式做定语通常要放在被修饰的词后，往往表示未发生的动作。例如：
I have a lot of work to do. 我有许多事要做。
There was nothing to bring home that morning. 那天早上（他回家时）两手空空。
7、 不定式作状语
1）目的状语
常用结构为to do , only to do（仅仅为了）, in order to do, so as to do, so （such ）… as to…（如此…以便…）。例如：
He ran so fast as to catch the first bus. 他飞快地跑以便赶上第一班车。
I come here only to say good-bye to you. 我来仅仅是向你告别。
2）作结果状语，可以表示没有预料到的或事与愿违的结果，不定式要放在句子后面。 I awoke to find my truck gone. 我醒来发现我的搬行李的手推车不见了。
He searched the room only to find nothing. 他搜索了房间，没发现什么。
3） 表原因
I'm glad to see you. 见到你很高兴。
She wept to see the sight. 她一看到这情形就哭了。
4）表示理由和条件
He must be a fool to say so.
You will do well to speak more carefully.
8、用作介词的to
to 可以用作介词，也可用作不定式的标示。下面的to 都用作介词：
admit to object to be accustomed to be used to stick to turn to（开始） look forward to be devoted to pay attention to contribute to apologize to devote oneself to
9、 省去to 的动词不定式
1） 情态动词 （ 除ought 外） 后。
2） 使役动词 let, have, make后，感官动词 see, watch, look at, notice , observe, hear, listen to, smell, feel, find 等后。
注意：被动语态中不能省去to 。例如： I saw him dance. =He was seen to dance.
The boss made them work the whole night. =They were made to work the whole night.
3） would rather，had better句型后
4） Why… / why not…句型后
5） help 后可带to ，也可不带to, help sb （to ） do sth.
6） but 和except 后。but 前是实义动词do 时，后面出现的不定式不带to 。
比较：He wants to do nothing but go out. 他只想出去玩。
He wants to believe anything but to take the medicine. 除了吃这药，他什么都信。
7） 由and, or和than 连接的两个不定式，第二个to
可以省去：
8） 通常在discover, imagine, suppose, think等词后作主补时，可以省去to be。例如： He is supposed （to be） nice. 他应该是个好人。
典型例题
1） ---- I usually go there by train.
---- Why not ___ by boat for a change?
A. to try going B. trying to go
C. to try and go D. try going （D ）
2） Paul doesn't have to be made ___. He always works hard.
A. learn B. to learn C. learned D. Learning （B ）
10、动词不定式的否定式
在不定式标志to 前加上not 。例如：
Tell him not to shut the window。
She pretended not to see me when I passed by.
典型例题
1）Mrs. Smith warned her daughter ___ after drinking.
A. never to drive B. to never driver
C. never driving D. never drive （A ）
2） The boy wanted to ride his bicycle in the street，
but his mother told him ____.
A. not to B. not to do
C. not do it D. do not to （A ）
说明：not to 为not to do it 的省略形式。
不定式的特殊句型
1、不定式的特殊句型too+形容词／副词+不定式 ：“太…以至于不能…”。
1）例如：He is too excited to speak. 他太激动了，说不出话来。
She works too slowly to be much use to me．
她干活太慢，对我不会有多大帮助。
Well, I'm afraid the box is too heavy for you to carry it, but thank you all the same.
不用了。这箱子太重，恐怕你搬不动。谢谢。
2） 如在too 前有否定词，则整个句子用否定词表达肯定，too 后那个词表达一种委婉含义，意 为" 不太" 。例如： It's never too late to mend.改过不嫌（谚语）
3） 当too 前面有only, all, but时，意思是：非常… 等于very 。例如：I'm only too pleased to be able to help you. 能帮助你我非常高兴。He was but too eager to get home. 他非常想回家。
2、不定式的特殊句型so as to
1） 表示目的；它的否定式是 so as not to do。例如：
T om kept quiet about the accident so as not to lose his job.汤姆对事故保持沉默是为了不丢掉他的工作。
Go in quietly so as not to wake the baby.轻点进去，别惊醒了婴儿。
2）表示结果。例如：
Would you be so kind as to tell me the time? 劳驾，现在几点了。
3、不定式的特殊句型Why not
"Why not +动词原形" 表达向某人提出建议，翻译为：" 为什么不……?" "干吗不……?"。例如： Why not take a holiday? 干吗不去度假?
4、不定式的特殊句型形容词／副词+enough +不定式
（a ）如在too 结构中一样，不定式可以指动词的主语而言：
She is old enough to travel by herself．
He didn‟t jump high enough to win a prize．
（b ）这种结构还可以指动词的宾语而言：
After a few minutes the coffee was cool enough（for us） to drink．(…the coffee was so cool that we can drink it)
He spoke slowly enough for everyone to understand．
（c ）这种结构也可以指介词的宾语而言：
The ice was thick enough to walk on．不定式时态和语态
1） 一般式表示的动词，有时与谓语动词表示的动作同时发生，有时发生在谓语动词的动作之
后，例如： He seems to know this. 他似乎知道这事。
I hope to see you again. = I hope that I'll see you again. 我希望再见到你。
2） 完成式表示的动作发生在谓语动词表示的动作之前。例如：
I'm sorry to have given you so much trouble. 很抱歉，给你添了那么多的麻烦。
He seems to have caught a cold. 他好像已经得了感冒。
3） 进行式表示动作正在进行，与谓语动词表示的动作同时发生。例如：
He seems to be eating something. 他好像正在吃什么东西。
4） 完成进行式表示动作从过去开始并延续至说话的时候。例如：
She is known to have been working on the problem for many years. 我们知道她研究 这问题有好几年了。
动名词与不定式 ：
1、1）动名词与不定式的区别：
动名词表达的是： 状态，性质，心境，抽象，经常性，已发生的
不定式表达的是： 目的，结果，原因，具体，一次性，将发生的
2）有些动词后面跟不定式或动名词作宾语，意义基本相同。
3）有些动词后面跟不定式或动名词作宾语，意义大相径庭。
2、特殊词精讲：
1） stop doing/to do
stop to do 停止，中断做某事后去做另一件事，stop doing 停止做某事。例如：
They stop to smoke a cigarette. 他们停下来，抽了根烟。
I must stop smoking. 我必须戒烟了。
2） forget doing/to do
forget to do 忘记要去做某事，forget doing 忘记做过某事。例如：
The light in the office is still on. He forgot to turn it off. 办公室的灯还在亮着，他忘记关了。（没有做关灯的动作）
He forgot turning the light off. 他忘记他已经关了灯了。（已做过关灯的动作）
3) remember doing/to do
remember to do 记得去做某事，remember doing 记得做过某事。例如：
Remember to go to the post office after school. 记着放学后去趟邮局。
Don't you remember seeing the man before? 你不记得以前见过那个人吗?
4） regret doing/to do
regret to do 对将要做的事遗憾，regret doing 对做过的事遗憾、后悔。例如：
I regret to have to do this, but I have no choice. 我很遗憾必须这样去做，我实在没有办法。 I don„t regret telling her what I thought. 我不为告诉她我的想法而后悔。
5） cease doing/to do
cease to do 长时间，甚至永远停做某事，cease doing 短时停止做某事，以后还会接着做。例如：
That department has ceased to exist forever. 那个系已不复存在。
The girls ceased chatting for a moment when their teacher passed by. 姑娘们在老师走过时，停了会聊天。
6） try doing/to do
try to do 努力，企图做某事，try doing 试验，试着做某事。例如：
You must try to be more careful. 你可要多加小心。
I tried gardening but didn„t succeed. 我试着种果木花卉，但未成功。
7） go on doing/to do
go on to do 做了一件事后，接着做另一件事，go on doing 继续做原来做的事。例如： After he had finished his maths，he went on to do his physics. 做完数学后，他接着去做物理。 Go on doing the other exercise after you have finished this one. 作完这个练习后，接着做其他的练习
8） be afraid to do ／of doing
be afraid to do 不敢，胆怯去做某事，是主观上的原因不去做，意为" 怕" ，be afraid of doing 担心出现doing 的状况、结果。doing 是客观上造成的，意为" 生怕，恐怕" 。例如：
She was afraid to step further in grass because she was afraid of being bitten by a snake. 她生怕被蛇咬着，不敢在草丛中再走一步。
9) be interested to do /in doing
interested to do 对做某事感兴趣，想了解某事，interested in doing 对某种想法感兴趣，doing 通常为想法。例如：
I shall be interested to know what happens. 我很想知道发生了什么事。（想了解）
I'm interested in working in Switzerland.
Do you have any idea about that?
我对在瑞士工作感兴趣。你想过这事吗? （一种想法）
10) mean doing/to do
mean to do 打算、想，mean doing 意味着。例如：I mean to go, but my father would not allow me to. 我想去，但是我父亲不肯让我去。T o raise wage means increasing purchasing power. 增加工资意味着增加购买力。
11) begin（start ） doing/to do
1） 谈及一项长期活动或开始一种习惯时，使用doing 。例如：
How old were you when you first started playing the piano? 你几岁时开始弹钢琴？
2） begin, start用进行体时，后面动词用不定式to do。例如：I was beginning to get angry。
我开始生起气来。
3） 在attempt, intend, begin, start 后接know, understand, realize这类动词时，常用不定式to do。
例如：I begin to understand the truth。我开始明白真相。
4） 事物作主语时。例如：The snow began to melt.雪开始融化了。