1 在感官动词和使役动词之后
在感官动词及使役动词后省去to感官动词有：feel，hear，see，watch，notice，observe，listen to，look at
使役动词有：let，make，have
注意have，make，只在当使役动词时才省去不定式作宾补时的小品词to，否则不省略to。
They made a lot of paper flowers to decrate the room.
他们生产了许多纸花装饰这个房间。
（made 不当使役动词，没有“使得”这一意思，因此不能省略不定式的小品词to）
Next month we’ll have a lot of meetings to attend.
下个月我们要参加许多会。
2 有两个以上的不定式并列
当两个或两个以上的不定式并列在一起时（尤其是用连词and 或or连接时），第二个不定式小品词to 可以省略。I promised to finish my homework and hand it in on time.
我答应（保证）完成作业并按时交上。
The guard hardly knew whether to laugh or cry.
卫兵简直哭笑不得。
如果用逗号代替了连词and、or 的位置，第二个动词不定式的小品词一般要保留，有时也可以省略。
I promised to finish my homework, (to)hand it in on time.
我答应完成作业并按时交上。
The boy likes to stay with his brothers, (to)play basketball
on the playgroud.
这个男孩子愿意和他的兄弟们呆在一起，打篮球。
注意
在对照的场合，to 不可以被省掉。
It’s better to laugh than to cry.
笑比哭好。
I haven’t decided to watch football game or to stay at home
this evening.
今天晚上是看足球赛还是呆在家里，我还没决定下来。
3 有介词but，except，besides
当介词but，except，besides 前面有实义动词do 时，不定式在介词之后可以省去to。比较
They enemy can do nothin but (except) surrender.
敌人除了投降之外，别无出路。
What does he like to do besides read novels?
=What does he like besides to read novels?
除了看小说之外，他还喜欢别的吗？
The enemy had nothing to choose but (except) to surrender.
敌人除了投降之外，别无选择。
4 在下列固定词组句型中
had better（had best）+原形不定式 最好had better（had best）not+原形不定式 最好不要
would（had）rather（sooner）+原形不定式+than+原形不定式
would（had）as soon+原形不定式+as+原形不定式
宁愿……而不愿
原形不定式不得不～（参见． ） doing nothing（=not do anything）but（或expect）+原形不定式
只～（参见P．86）
You had better not go.
你最好别走。
He would rather look after the baby than do his homework.
他宁愿看管这个婴儿也不愿意做作业。
I can’t but think so.
我不得不这样想。
You have nothing to do but wait.
你只有等待。
5 做宾语的不定式重复时
当作宾语的不定式重复时，只保留to，为了避免重复，作宾语的不定式再次出现时往往省略，只保留不定式符号to。（参见P．71 不定式 作宾语）1．在want，wish，like，hate，hope，try，plan，love⋯ 后
Do you want to have a rest?
你想休息一会儿吗？
Yes, I want to, but I can’t.
想啊，但是不行。
Did you get the new stamps?
你买到新邮票了吗？
No, I tried to, but there wasn’t any left in that post office.
没有，我去买了，可是那个邮局里全卖完了。
2． 在have，ought，need 等词后
I didn’t mean to call you at late night, but I had to as I
did have something important to tell you.
我本不打算深夜给你打电话的，但不得不给你打，因我确实有重要
的事要告诉你。
3．在be able，used 和be going (to)之后
I’m going to the south next week. What about you?
我下周准备去南部，你呢？
I’m going to.
我也打算去。
（此部分还可参考本章中P．71 不定式作宾语部分）
6 在go，come 后面作目的状语的不定式（△△）
口语中用在动词go 和come 后面作目的状语时，to 常可省略，尤常见于祈使句中，也可用于陈述句，但go 和come 只能是现在式形式而不
是过去式。
Please come sit here.
请过来坐在这儿。
Go ask your father.
去问问你爸爸。
you should go say “thank you”.
你应该去说一声“谢谢”。
7 在系动词be 后作表语时
当不定式在系动词后作表语时，如果主语部分带有实义动词do，就可以省去to。
The only thing I can do is lie in bed.
我唯一能做的事就是躺在床上。
What I want to do is have a good rest.
我想要做的事就是好好休息一下。
8 句型why not do sth?/Why do sth?
Why not?（Why not do sth?）形式上虽然是否定的，但意思上是肯定的，是鼓励人们去做。口语中经常用它。
Why do sth?则相反，形式上是肯定的，意思上则是否定的，不鼓励
人们去做。
Today is Sunday. Why not go out to relax yourself?
今天是周日，干嘛不出去轻松一下呢？
（今天是周日，你最好出去放松一下。）
I hear“Titanic”is very good. I want to see it. How about you?
我听说“泰坦尼克号”这个电影非常好，我想去看它，你呢？
Why not? When?
当然去了。什么时候？
（为什么不去呢？什么时候去呢？）
9 几个句型和词组
1．prefer and would rathera．prefer 和like，love 一样，后面可以跟不定式或动名词。
I don’t like cities. I prefer to live in the countryside.
=I don’t like cities. I prefer living in the countryside.
我不喜欢城市。我愿意（喜欢）住在乡村。
b．⋯prefer + n/doing（动名词）to + n/doing（动名词）
喜欢⋯⋯而不喜欢⋯⋯；宁愿⋯⋯而不愿⋯⋯
I prefer meat to fish.
我喜欢肉而不喜欢鱼。
He prefers listening to music to playing football.
他喜欢听音乐而不喜欢踢足球。
（他宁愿听音乐，也不踢足球）
c．⋯prefer+to do sth. rather than (to) do sth.
⋯⋯宁愿⋯⋯而不愿⋯⋯
注意
would rather 句型的否定式，应将not 放在rather 之后，不可放在
would 之后，但缩写时例外。
I would rather not walk.
我不愿走路。
Wouldn’t you rather walk?
你不愿走路吗？
I prefer to go to the movies rather than(to) stay home.
I prefer going to the movies to staying home.
我愿意看电影而不愿意呆在家里。
She prefers to travel rather than attend the wedding.
She prefers traveling to attending the wedding.
她宁愿去旅行也不愿参加这个婚礼。
d．would rather do sth.
would rather not do sth.
Shall we go by train?
我们坐火车好吗？
I would rather go by car.
我还是愿意坐小汽车去。
I’m tired, I’d rather not go out this evening, if you don’t
mind.
我累了。如果你不介意的话，今天晚上我（宁愿不出去）不想出去。
e．would rather do sth. than (do) sth. else
宁愿⋯⋯而不愿
I’d rather stay at home tonight than go to the cinema.
今天晚上我宁愿呆在家里而不愿意看电影。
f．⋯would rather + 句子（过去时）（虚拟语气）
你要做⋯⋯
Shall I stay here?
我可以呆在这儿吗？
I’d rather you came with us.
你还是和我们一起来吧。
I’d rather cook the dinner now. And I’d rather you cooked the
dinner now.
我现在愿意做饭。我想你现在也应该做饭。
（would rather 后面的句子要用过去时，不表示时态，而只是一种
语气，所以这个句型是虚拟语气的一种。）
I’d rather you didn’t tell anyone what I said.
你最好别告诉任何人我所说的话。
注意
否定时，是否定后面的句子。
2．advise，allow，permit，forbid 的用法
a．advise/allow/permit/forbid doing sth.
He advised going at once.
他建议立即走。
She doesn’t allow smoking in the house.
她不允许在这个房间吸烟。
The policeman permitted his parking there.
警察不允许他在那里停车。
My parents forbade my watching TV except on Sundays.
除了周日外我父母不准我看电视。
b.advise/allow/permit/forbid sb. to do sth.
The doctor advised me to stop smoking.
医生建议我（别吸烟）戒烟。
She doesn’t allow us to smoke here but she allows herhusband
to smoke here.
她不允许我们在这儿吸烟，但允许她丈夫在这儿吸烟。
The policeman permitted him to park there.
警察允许他在那里停车。
My parents forbade me to watch TV except on Sundays.
我的父母禁止我看电视，除了周日以外。
3.want/wish/promise/hope+不定式
其用法的注意事项（请看初级版中第十四章不定式部分P.186）
4.prevent/save/keep/stop⋯from(doing)sth.
阻止某人做某事
a. prevent/stop sb. from(doing)sth.
此句型中from 可以省略，但在被动语态中from 不可省去。
There was nothing to prevent her(from)doing so.
没有什么东西能阻止她这样做。
比较
That’s the best way to prevent such a thing(from)happening
again.
这是防止这种事情再发生的最好办法。
He was prevented by illness from joining in the expedition.
（被动语态）
他因病未能参加这次探险活动。
比较
We all tried to stop him(from)smoking in bed.
我们都不让他在床上吸烟。
We were stopped by him from making any noise.（被动语态）
他不让我们发生任何噪音。
b. save sb. from doing sth.
The climbers put a rope round themselves to save the mfrom
falling.
攀登者身上系着绳子，以防摔落下去。
c. keep sb. from doing
注意
此句型中from 不能省略。
Can’t you keep him from forgetting?
难道你能让他不忘掉什么吗？
（难道你能防止避免他忘记什么吗？）
What shall I do to keep this from getting dirty?
我该怎么办才能不把这东西弄脏呢？
forbid sb. to do sth.
forbid sb. to do sth. 也是阻止某人做某事的意思。
Their parents forbade them to go.
他们父母亲不让他们去。
He was strictly forbidden to drink tea.
他被严格禁止喝茶。
5. suggest 当“建议”讲时
a. suggest +名词或代词
She suggested a way out of the difficulty.
她提出了一个克服困难的办法。
b. suggest +动名词I suggested putting the meeting off.我建
议会议延期。He suggested my(me) staying here.
他建议我待在这里。
c. suggest +从句（主语+should +V.）
should 可省略。
The teacher suggested that the students
(should)relaxthemselves on Sunday.
老师建议学生们周日去放松一下。
He suggested that we(should)come another day.
他建议我们改天再来。
suggest 当“表明”讲时，后面接宾语从句，用陈述语气。
On the boy’s face there was a half-smile that seemed to suggest
that he was happy to have given his life for his country.
小男孩脸上的微笑表明他很幸福，因为他已经把他的生命献给了他
的国家。
His pale face suggests he is in poor health.
他脸色苍白，说明他身体不好。
Her expression suggested that she was angry. (happy, sad,
satisfied, frightened⋯)
她脸上的表情表明她生气（愉快、难过、满意、害怕⋯⋯）。
注意
suggest 后不跟不定式
(×)suggest to do sth.
(×)suggest sb. to do sth.