高中语法——不定式
发布时间:2020-03-07 01:30:50浏览次数:52025
动词不定式是动词的一种非谓语形式,在句中不能单独作谓语。动词不定式具有动词的性质,它可以有自己的宾语和状语,从而构成动词不定式短语。
它还可以有形式的变化,即一般式、进行式、完成式和被动式。
同时,动词不定式也具有非动词的性质,相当于一个名词、形容词或副词,可以在句中担任主语、宾语、宾语补足语、表语、定语和状语。
动词不定式是由不定式符号to+动词原形构成,在某些情况下to也可省略。
不定式的一般式表示的动作通常与主要谓语的动作同时或几乎同时发生,或是在它之后发生。
He appears to be very happy.
不定式的进行式表示正在进行的或与谓语动词同时发生的动作。
It happened to be raining when I got there.
不定式的完成式表示的动作在谓语表示的动作之前发生。
I'm sorry to have lost your key.
不定式的完成进行式表示的动作在谓语之前发生并且一直进行着。
He was said to have been living in London for twenty years.
据说他在伦敦一直住了20年。
【比较】不定式的时态意义:
He is said to be studying abroad.
据说他正在国外读书。(不定式的进行式表示动作正在进行)
He is said to have studied abroad.
据说他在国外学习过。(不定式的完成式表示动作已经结束)
当不定式逻辑上的主语是这个不定式表示的动作的承受者时,不定式一般要用被动形式。不定式的被动形式根据其与谓语动作发生的先后关系,有一般式和完成时两种。
1、一般式to be done
These are the books to be given out to the students.
这些是要发给学生的书。
2、完成式to have been done
The novel is said to have been translated into many languages.
不定式的否定形式由not或never加不定式构成。
We decided not to go out because of the bad weather.
由于天气不好,我们决定不出去。
【注意】谓语动词的否定和不定式的否定不同的意义:
I did not promise to wake him up.
I promised not to wake him up.
动词不定式除了不能单独作谓语外,几乎能担任句子中所有的句子成分。
To know oneself is difficult.
在很多情况下,人们通常用it作为形式上的主语,而把不定式移到谓语之后,使句子结构显得平稳一些。
It's rude to turn your back to your teacher and refuse to answer.
背对着老师,拒绝回答问题是不礼貌的。
【注意】当主语和表语都是不定式时,不能用形式主语代替动词不定式。
To respect others is to be respected.
His wish is to become an astronaut.
他的愿望是成为一名宇航员。
【注意】有些作表语的不定式,在结构上是主动的,但在意义上却是被动的。
不定式可以充当部分及物动词的宾语,也可以充当but和except等介词的宾语以及形容词的宾语。
Father likes to listen to music in silence.
父亲喜欢静静地听音乐。
【必背】可接不定式作宾语的动词有:
afford负担得起
agree同意
aim以……为目标
ask要求
attempt尝试
begin开始
care喜爱
choose决定
continue继续
decide决定
desire要求
determine决心
expect期待
fail不能
forget忘记
hate不愿
hope希望
intend打算
manage设法
mean打算
offer表示愿意
plan计划
prefer宁愿
pretend假装
promise答应
refuse拒绝
remember记起
try努力
want想要
wish希望
(2)在feel, find, make, think,consider等动词后,如果宾语带有宾语补足语时,人们常常用it作形式宾语,而把真实宾语放在宾语补足语之后。
I found it possible to work out the problem without a computer.
我发现有可能不用计算机而解出这道题目。
(3)在表示“希望、打算”等动词(如hope,expect, intend, mean, want等)的过去式后,可接动词不定式的完成式来表示没有实现的动作。
I intended to have called on you, but was prevented from doing so.
我原想来拜访你的,但没来成。
【提示】表示“原打算、原以为”还可以用这类动词的过去完成时来表达。
I had expected to meet him here last night.
The teacher made no comments except to tell him to work hard.
老师除了叫他努力学习外,未做任何评价。
3、作形容词的宾语
不定式作形容词的宾语有两种句型,一个是句子的主语是不定式的逻辑主语,另一个是句子的主语是不定式的逻辑宾语。
(1)句子的主语是不定式的逻辑主语。这类形容词有able,afraid, angry, anxious, careful, clever, content, cruel, determined,disappointed, eager, foolish, fortunate, frightened, happy, impatient, glad,lucky, naughty, prepared, proud, ready, slow, shocked, sorry, surprised,willing等。
I am sorry to say that he is going from bad to worse.
很遗憾,他的情况每况愈下。
(2)句子的主语是不定式的逻辑宾语。这类形容词有easy,hard, cheap,expensive, dangerous, difficult, funny, fit, impossible,interesting, nice, pleasant, simple, strange, useful等。
This problem is easy to solve.
这个问题很容易解决。
【注意】在这种结构中,如果不定式是不及物动词,则必须加上结构或含义所需的介词。
The river is dangerous to swim in.
不定式可以在“主语+谓语+宾语+宾语补足语”句型中充当宾语补足语。在这一句型中,宾语是动词不定式的逻辑主语。
1、在表示感觉的动词后作宾语补足语,并且不定式都不带to。这类动词有:see,hear, feel, watch, notice, observe, look at, listen to等。
I heard them sing yesterday.
昨天我听见他们唱歌了。
【注意】转为被动语态时,原不带to的不定式要变成带to的不定式。notice和watch没有被动语态。
We saw the car stop.
→The car was seen to stop.
我们看见这辆车停了下来。
2、在使役动词后作宾语补足语,不定式不带to。
这类动词有:make,let, have等。转为被动语态时,其后通常都用带to的不定式(have没有被动语态)。
有些动词跟不定式作宾语补足语时省去了to,这些动词有:一感二听三让四观看。
四观看:observe,see,watch,look at
She made him give up smoking.
3、在表示心理状态的动词后作宾语补足语。这类动词有:consider,think, believe, discover, find, imagine, judge, suppose, prove等。这类动词后的不定式通常是“to be+形容词或名词”结构,think, consider, find后的tobe常可省略。
We consider him (to be) a good teacher.
我们认为他是一个好老师。
4、在表示情感状态的动词后作宾语补足语。这类动词有:love,like, prefer, hate, want, wish, expect等。
I'd prefer you to leave him alone.
我希望你不要打扰他。
5、动词advise,allow, ask, beg, command, tell, invite, force, oblige, get, help, encourage,persuade, permit, remind, request, order, warn, cause等后面,多接不定式短语作宾语补足语。
We don't allow such things to happen again.
我们不容许这种事情再发生。
【注意】hope,demand, suggest等动词后面不能接不定式作宾语补足语。
(误)I hope you to give me a hand.
(正)I hope you can give me a hand.
(正)I wish you to give me a hand.
(误)He demanded me to be present at the meeting.
(正)He demanded that we should be present at the meeting.
(正)He required us to be present at the meeting.
(误)Mr Li suggested her not to go there alone.
(正)Mr Li suggested that she should not go there alone.
I'm waiting for James to arrive.
我正等着詹姆斯的到来。
【必背】这些带介词的短语动词有:
call on号召
arrange for安排
long for盼望
wait for等待
depend on依靠
relyon指望
不定式作定语通常放在其修饰的名词或代词之后,和被修饰的名词或代词之间是主谓关系、动宾关系、同位关系和修饰关系。
The future to greet us will be bright.
On Sundays, he always has a lot of letters to write.
星期天,他总是有许多信要写
【注意】由于动词不定式与其修饰的词之间往往有动宾关系,因此,如果该不定式是不及物动词,其后应有必要的介词。
She has a child to take care of.
He broke his promise to write to his parents regularly.
Now it is time to begin our class.
不定式作状语可以表示行为的目的、结果、原因、条件等。
1、表示目的
I'm saving up to buy a computer.
我在存钱买电脑。
【注意】有时为了强调或突出这种目的,也可以用inorder (not) to do,和so as (not) to do结构(soas to do不可以置于句首)。
He shouted and waved in order to be noticed.
He got to the station only to find the train had gone.
他赶到车站,发现火车已经开走了。
【必背】不定式表示结果常见于下列句型。
Would you be so kind as to lend me your bicycle?
We are not such fools as to believe him.
He didn't run fast enough to catch the train.
He lifted a rock only to drop it on his own feet.
His eyesight is too poor to read such small letters.
【注意】too...to...结构中的形容词如果是eager,pleased, happy, ready等,动词不定式不表示结果,也没有否定的意思。
The boy was too eager to get a geography book.
He is too anxious to know the examination results.
I was a fool not to listen to you at that time.
A man would be blind not to see that.
动词不定式的逻辑主语(即不定式动作的执行者)通常是句子的主语或宾语。如果不定式的逻辑主语不是句子的主语,此时一般用“for +名词(代词)+不定式”来构成不定式的复合结构,这种复合结构在句中可以做主语、宾语、表语、状语、定语。
This box is too heavy for the little boy to carry.
“be +不定式”结构可以表示将来发生的动作,常有以下两种情况:
The room is to be locked.
We are to begin the work next month.
疑问词who,what, which, when, where, how, why后加动词不定式构成不定式短语,它在句中可作主语、宾语和表语。
I don't know whether to go to the meeting or not.
“with/without +名词+不定式”结构在句子中通常起状语的作用。
With so much work to do, I shall not be able to go to the cinema with you.
(五)It is +形容词+ for/of sb + to do结构
在“It is +形容词+of sb +不定式”结构中,形容词往往表示人物的性格和特征,如kind,silly, good, unwise, clever, wrong, right, foolish, stupid, careless, rude,impolite, bold, thoughtful, honest, bad, sensible, naughty等。
在“It is +形容词+for/sb +不定式”结构中,形容词通常表示事物的性质,如important,possible, impossible, necessary, difficult, hard, reasonable等。
It's kind of you to think so much of us.
(=You are kind to think so much of us.)
It is good lf you to help me with my English.
(强调you的特征=Youare good to help me.)
It is good for you to give up smoking.
(强调的是give up smoking这一行为=For you to give up smoking is good.)
动词不定式to do通常是不拆开的,但偶尔也可在不定式符号to和动词原形之间插入一个副词,构成分裂不定式。
He was too ill to completely carry out that program.
有一些不定式短语可以作状语修饰整个句子,也可被称为插入语。
To be honest, we are not sure to find the girl in the forest.
说老实话,我们不能确保在森林里能找到那个女孩。
【必背】用作独立成分的不定式:
to tell you the truth说老实话
to be frank 坦率地说
to begin with首先
to be brief简言之
to make a long story short长话短说
to be exact精确地说
to say nothing of姑且不说
to conclude总而言之
to be sure诚然,固然
to do him justice说句对他公道的话
so to speak可以这么说
动词不定式在句中究竟用主动还是被动,有时比较复杂,主要有下面几种情况:
1、不定式做后置定语,和被修饰的名词或代词构成逻辑上的动宾关系,但又和该句主语构成逻辑上的主谓关系时。
Do you have anything to say on this question?
针对这个问题你有什么要说的吗?
2、不定式作形容词的宾语,和句子主语构成逻辑上的动宾关系时。
The book is difficult to understand.
这本书很难理解。
3、There be结构中,当说话人考虑必须有人去完成某件事时。
There is nothing to worry about.
There is a lot of work to do.
There is a lot of work to be done.
She has two letters to type.
She has two letters to be typed.
I hoped to have met him at the railway station, but he didn't turn up.
We would love to have gone to the match, but the tickets were all sold out.
The plane was to have taken off at 9, but something went wrong.
不定式可用于感叹句,含有惊异、不满、惋惜或赞美等感情色彩。
To think that he should do this!
Oh, God,to see her dance !
To think that all the money has been wasted!
1、在口语中,动词原形come和go后可接不带to的不定式。
2、在why引起的一些问句中,疑问词直接跟动词原形或not+动词原形。
为什么不加入我们?
3、在hadbetter, had best, would rather, would rather...than, would sooner, would sooner...than,cannot but, cannot choose but, cannot help but等结构后直接跟动词原形或not+动词原形。
You'd better listen to your teacher's opinion.
We had best call for the doctor at once.
She can't do anything but ask silly questions.
Rather than ride on a crowded bus, he always prefers to ride a bicycle.
He cannot but move to another street, because his building has to be pulled downsoon.
他不得不搬到另一条街上去,因为他住的大楼很快就要被推倒。
We cannot help but admire his courage.
我们情不自禁地钦佩他的勇气。
4、如不定式前有行为动词do,那么在表语从句中的不定式和介词except或but之后的不定式可不带to。
The only thing I could do was go home.
They could do nothing but wait for the doctor to come.
他们只能等待医生的到来。
5、在两个动词不定式并列使用时,为了避免重复,后面的不定式符号to可省略。
The little girl hardly knew whether to laugh or cry.
Can you help me to call him and ask him to attend the meeting at 2 p.m?
你能不能帮我打电话给他,叫他下午两点来开会?
6、在help之后,既可用带to的不定式也可用不带to的不定式。
Can I help (to) carry the box for you?
我帮你搬箱子,好吗?
7、在一些固定搭配中用不带to的不定式。
I hear say there will be an earthquake soon.
She made believe she was innocent.
她假装清白。
8、在感官动词see,hear, watch, feel, notice以及使役动词make,let, have等后作宾语补足语的动词不定式不带to。
She watched the children cross the street.
They made the boy apologize to his friend for being so rude.
Don't forget to have him come earlier.
为了避免重复上文中出现过的动词,可以用不定式符号to来代替上文中出现过的不定式结构。
1、在助动词或情态动词之后,如begoing to, used to, have to, ought to, be able to, be about to等。
She must go but you don't have to.
她必须走,但你没有必要。
2、在want,decide, like, love, hope, wish, mean, refuse, try等动词之后。
You may go with them if you hope to.
如果你希望的话,你可以和他们一起去。
3、在做宾语补足语的ask,tell, order, advise, persuade, warn, wish, permit, allow, forbid等动词之后。
Don't do anything unless your father tells you to.
除非你父亲叫你去做,不然不要做任何事情。
4、在对话的答语中的happy,glad, eager, anxious, willing, ready, pleased, afraid等形容词之后。
—Will you lend me a hand?
—I'm willing to, but I can't now.
【提示】如果动词不定式是tobe或to have,则一般不省。
—Did you finish the work?
to既可以是不定式符号,后接动词原形;to也可以是介词,后接名词或动词的-ing形式。英语中有很多常用短语带有to,我们要正确判断to是不定式符号还是介词,千万不可混淆。
1、不定式符号to
He made it a rule to read English aloud for half an hour every morning.
These young lads are longing to go to watch the football match.
be determined to do决心要做某事
have the nerve to do有胆量做某事
have agreat mind to do很想做某事
make up one's mind to do决定做某事
take the trouble to do不辞辛苦地做某事
prepare oneself to do有思想准备做某事
2、介词to
If you stick to the truth, you will have nothing to fear.
You must get used to getting up early.
Isn't it time you got down to marking those papers?
难道还没到你定下心来阅卷的时间吗?
【必背】常见的带介词to的短语:
be used to习惯
be equal to胜任
be given to沉溺于
be opposed to反对
be related to与……有关
devote oneself to献身于
get down to着手做
give rise to引起
lead to导致
look forward to盼望
object to反对
pay attention to注意
put one's mind to全神贯注于
stick to坚持