如题所述
在英语语法中,不定式是指动词中的一种不带词形变化从而不指示人称、数量、时态的一种形式。
它之所以被称做不定式,是因为动词不被限定,或者说不被词形变化所局限。不定式属于非谓语动词形式。
动词不定式可以作以上各种成分,但它毕竟是动词,所以有动词的属性。
扩展资料
动词不定式及其短语还可以有自己的宾语、状语,虽然动词不定式在语法上没有表面上的直接主语,但它表达的意义是动作,这一动作一定由使动者(动词的使用者)发出。
对于英语来说接不定式的单词多为“打算”“计划”“希望”“将要做某事”等表示未来(未做的事)的动词。同样与不定式表示不同,现在分词表示正在进行,一般性或经常性发生的行为。
如果动词不定式的逻辑主语是这个不定式所表示的动作的承受者,不定式一般要用被动语态形式。如:
It's a great honour to be invited to Mary's birthday party.(不定式作主语是被动语态to be invited是被邀请)——意思:能被邀请参加玛丽的生日聚会真是太荣幸了。
It was impossible for lost time to be made up.(不定式作主语)——意思:
弥补损失的时间是不可能的。
I wish to be sent to work in the country.(不定式作宾语)——意思:
我想被派到这个国家工作
1、不定式是一种,通常由"to+动词原形"构成,如to be,to do,to combine,to expand,to get up等。这里的to是不定式的符号,没有词义,有时还可以省略。
2、没有人称和数的变化。
3、不定式在句中不能单独用作谓语,但还保留着动词的若干特征:可以带状语,可以带宾语,可以带。
4、不定式可以连同它的附属成分一起组成不定式短语。
不定式的用法:不定式(短语)在句中起相当于名词、形容词或副词的作用,可作主语、表语、宾语、定语、状语和。
1、具有名词的性质
①用作主语。
例句:
(1)To live is to function.That is all there is in living.(Holmes)
活着就要发挥作用,这就是生活的全部真谛。
(2)To live of money is the root of all evil.(R.L.Stevenson)
迷恋金钱是一切罪恶的根源。
(3)To be ignorant of one's ignorance is the malady of the ignorant.(A.B.Alcott)不知道
自己的无知,是无知者的可悲之处。
ps:不定式、特别是不定式短语作主语时,为了保持句子平衡,往往把主语放在句子末尾,而在它原来的位置上加上引导词it作形式上的主语。
例句:
(1)To make you understand him completely is impossible.
→It is impossible to make you understand him completely.
让你们完全了解他是不可能的。
(2)To run machines needs power.
→It needs power to run machines.
开动机器需要动力。
(3)To remember to switch off the electricity is important.
→It's important to remember to switch off the electricity.
重要的是要记住关掉电源。
【注】"It is+形容词+of sb.to do"句型一般可转换成一个不定式作状语的句子,语义不变;而"It is+形容词+for sb.to do”句型则不可以。
②用作表语。
例句:
(1)Her wish was to become a teacher.
她的愿望是当个教师。
(2)The most dif?cult thing in life is to know yourself.(Thales)
人生最难是自知。
(3)To know everything is to know nothing.
样样都懂,样样稀松。
ps:1、带wh-疑问词的不定式短语可作表语。
例句:
Our difficulty is where to find a guide.
我们的困难是到哪里去找向导。
2、用介词for引出不定式的逻辑主语的不定式复合结构,可作表语;这时,句中的主语是不定式的逻辑宾语。
例句:This form is for you to fill in.
这张表格由你来填写。
③用作宾语。
例句:
(1)The owner wanted to make a large purchase of gift before Christmas.
老板想在圣诞节前做一大笔礼品生意。
(2)I try to keep that in mind.
我努力记住这一点。
(3)He had decided to return after receiving the first letter from Tess.
收到的第一封信后,他便决定起程回来。
ps:作宾语的不定式后面如果有补语,可以用it作形式宾语,把真正宾语置于补语之后,以免宾语太长使句子显得不协调。在这种用法中,常见的动词有think, feel, make, find, consider, count, deem,judge,believe,take等。
例句:
(1)She thought it unnecessary to quarrel with him over trifies.
她认为没必要为小事跟他争吵。
(2)I did not think it convenient to write about the matter.
我觉得写信谈这件事不合适。
(3)He found it utterly impossible to leave the spot.(T.Hardy)
他发现要离开这里是完全不可能的。
④用作宾语补语。
例句:
(1)I wanted something to happen to me,but nothing happened.(L.Hughes)
我希望在我身上会发生些什么变化,可是什么都没发生。
(2)I know nothing about him and I beg you to tell me nothing.
他的情况我并不知道,我也请求您别告诉我。
ps:在一些如make,let,have等和表示感觉的动词如see, watch, perceive, observe,notice,hear,feel,look at,listen to等,作宾语补语的不定式须省略to。
例句:
(1)She let her hand fall from his arm and said no more.
她放开他的胳膊,没再说什么。
(2)Electricity makes machines run.
电使机器转动。
(3)Then she turned quickly away,and Reinhard heard her go sobbing up the
stairs.
她很快转过身,听到她抽泣着走上台阶。
⑤用作主语补语。
例句:
(1)This test is thought to have practical value.
大家认为这个试验有实际价值。
(2)He was seen to enter the laboratory.
有人看见他走进了实验室。
⑥用作同位语。
例句:
Their aspiration,to become free and independent,is deserving of every kind
of help from us.
他们想自由和独立的愿望值得我们给予各方面的援助。
2、具有形容词的性质
①用作定语。
例句:
(1)Can you think up a good way to deal with the ever increasing prices?
你们能否想出一个对付日益上涨的物价的好办法?
(2)A letter from Clare gave her an excuse to leave.
的一封来信给了她一个离开的借口。
(3)At present I have no lawful right to act for her.
目前,我还没有保护她的法律权利。
ps:如果不定式和被修饰的具体名词之间有逻辑上的动宾关系,则不定式多半表示未来的动作,翻译时常须在不定式前加"要"字。
例句:
(1)We have three machines to repair today.
我们今天有三台机器要修理。
(2)Do you like something to drink?
你要喝点什么吗?
3、具有副词的性质
①用作状语。
目的状语:
例句:
(1)We use electrical energy to do many things.
我们用电能做许多事情。
(2)He will be in Atlanta Friday to speak with Captain Butler and to escort you
home.
星期五他要到,同船长交涉,顺便带你回家。
(3)John hurried in order not to be late for the party.
约翰急急忙忙的,为了准时参加晚会。
结果状语:
例句:
①After the war they parted company,never to see each other again.
战后他们分了手,从此再也没见过面。
②She went abroad never to return.
她到国外去了,从此没有回来过。
原因状语:
例句:
(1)He laughed to see such fun.
他看见这么可笑的事笑了。
(2)I trembled to think of it.
一想到这件事,我就不寒而栗。
(3)He jumped with joy to learn his being admitted to the university.
他知道被录取进大学高兴得跳起来。
条件状语:
例句:
(1)To hear him talk,you would think he owned the whole world.
如果你听他讲话,你会以为整个世界都是他的。
(2)A man would be blind not to see that.
一个人如果看不到这一点就是瞎子。
(3)They could have done better to have had some tools.
他们如果有些工具就会做得更好些。
方式状语:
例句:
(1)He cleared his throat as though to speak.
他清了清喉咙,好像要说话的样子。
(2)As if to justify his view,he cited some groundless rumors.
好像要证明他的观点正确似的,他引述了一些毫无根据的传闻。
比较状语:
例句:
(1)I know better than to believe such a man.
我不至于相信这样一个人。
(2)The American president had no better choice than to resign.
这个美国总统除辞职外,别无更好的选择。
让步状语:
例句:
(1)To do his best,he could not ful?l his task .
即使他竭尽全力,仍然不能按时完成任务。
(2)You couldn't do that to save your life.
你即使为了救自己的命也不能那样做。
4、用作插入语。
例句:
(1)To begin with,we must consider the problem in an all-round way.
首先,我们必须全面地考虑这个问题。
(2)Among the writers of his age,he was,so to speak,a giant among dwarfs.
在同时代的作家中,他可以说是鹤立鸡群。
(3)To tell you the truth,they didn't quite like the idea.
实话告诉你,他们并不很喜欢这种想法。
本回答被网友采纳动词不定式用作主语
不定式结构做主语,可以直接放于句首。但这样的用法不多见。
To hesitate(犹豫) is a pity.犹豫是件憾事。
To be here is a great pleasure.到这里是快乐的事情。
To remember to switch(关掉) off the electricity isimportant.记得关电是重要的。
现代英语一般使用形式主语it,把不定式后置。因此上面的句子一般这样表述:
Itis a pity to hesitate.犹豫不决真遗憾。
Itis a great pleasure to be here.很高兴来到这里。
Itis not sufficient to know the main facts.知道主要事实是不够的。
Itis important to remember to switchoff the electricity.要记得关掉电源是很重要的。
不定式用作表语
不定式作表语有两种情况要注意,一种是主语和表语都是不定式,主语是条件,表语是结果。这时,作表语的不定式不可以用动名词(doing)表示。
To see is to believe.百闻不如一见。 To decide is to act.下决心等于行动。
Tobe kind to the enemy is to be cruel to the people.对敌人仁慈就是对人民的残忍。
一种是,主语以这些名词表示:aim, ambition, duty, hope, idea,intention, mistake, plan, purpose, suggestion等;或主语以what引导的名词性主语从句表示,后面的不定式说明其内容。
Your mistake was not to write that better.你的错误是没有写得更好。
What I would suggest is to start work at once.我要建议的是马上开始干活。
My idea is to climb the mountain from the north.我的主意是从北边山爬山。
动词不定式作宾语
不定式作宾语有两种情形:
todo something (接不定式作宾语的动词:afford, agree, aim, apply, arrange,ask, choose, claim, decide, decline, demand, desire, determine, expect, hope,learn, long, manage, offer, pretend, promise, refuse, seek, threaten, want,wish等)
He pretended not to see me.他假装没看到我。
I expected to be back on Sunday.我可望在星期天回来。 What did he say he wanted to do? 他说过他想要做什么呢?
She asked to work only at weekend.她要求只在周末工作。 She applies to work only at weekend.她申请只在工作在周末。
Of course we hope to get a few more.当然我们希望得到更多一些。
He agreed to smoke no more cigarettes.他同意不再吸烟了。
She promises to make no mistake at all.她答应不再犯错误了。
不定式作宾语补足语
1表示感官的动词,不定式作宾语补足语时要省to,这类动词有:feel, hear, listen to,notice(无被动语态), observe, see, watch(无被动语态)等。转为被动语态时,不定式就成了主语补足语,这时的to要补上来。
Iheard her sing.我听到她唱歌了。
Thecar was seen to stop.车子有人看见停了。
2表“使役”的动词have,let, make等用不定式作宾语补足语也要省to,这3个动词中,have没有被动语态,make用于被动语态时也要把to补上来,而let的被动语态一般表示“出租”的意思;其他的“使役”动词不定式作宾语补足语时则不能省to,但都有被动语态。这些动词有:advise, allow, ask, beg,cause, drive, encourage, expect, forbid, force, get, invite, permit, persuade,remind, teach, tell, trust, urge, want, warn等。
Wewere made to wait outside.有人让我们在外面等。
3表示心里状态的动词,如:believe,consider, declare(宣称), discover, feel, find, guess,imagine, judge, prove, suppose, think, understand等。这类动词的宾语补足语一般是to be或to have done不定式,且在consider, declare, find,prove, think等之后的to be往往可以省略。
Iknow this to be a fact.我知道这是事实。
Wefound him (to be) dishonest.我们发现他不诚实。
示情感状态的动词:hate, like, love, prefer, want等。这时常用would跟hate, like, love, prefer搭配。这类动词一般不用被动形式。
I'dhate you to do that.我讨厌你那样干。 I'dprefer you to leave him.我宁愿你离开他。
I'dlove them to come tonight.我很想他们今晚来。 I don't want there to be any trouble.我不想有如何麻烦。
5还有一类不及物动词跟介词搭配,也可以用不定式作宾补,一般没有被动语态。这类动词有:arrange for, ask for, long for(期望), prepare for, providefor, vote for(赞成), wait for, wish for, call on/ upon, count on(指望), depend on/ upon, relyon等。
Wewaitfor that to be done.我们在等人那件事。 I will arrange for you to come.我将为你来做安排。
Youcan't rely on him to assist you.你不能靠他辅助你。 Shall we ask for Mary to come too? 我们可以请玛丽也来吗?
动词不定式作定语
动词不定式作定语跟中心词有逻辑关系,大致分为主谓关系、动宾关系、同位关系和状语关系等。不定式在句中做定语通常做后置定语,即放在被修饰名词或代词后。
1 主谓关系:不定式的动作是不定式所修饰的中心词来执行。可以改成定语从句。
1) 不定式还可用来修饰人。
He is a man tofinish his task best.他是完成任务最好的人。
He was a brave man todo what he did.他是个敢做敢当的勇敢之人。
2) 不定式常可用来修饰物,表示某物要做某事。
The next train toarrive (which would arrive) was from New York.下一列到站的火车是从纽约开来的。
The next bus toarrive (which arrives) here may be late half an hour.下一趟到这里的公汽可能晚到半小时。
2 动宾关系:不定式所修饰的中心词跟不定式有动宾关系。可改成定语从句。跟主谓关系一样,不定式修饰的既可以是人,也可以是物。不定式动作的执行者可能是句子的主语,也有可能是句子的宾语(见不定式的被动式);有时不定式动作的执行者暗含在上下文中;有时用for somebody/something指出动作的执行者;有时根本不知道是谁。
1) 及物动词不定式:动词不定式直接放在所修饰的中心词之后。
This is adelicious cake for you to eat (which you can eat).这是一个给你吃的美味蛋糕。
Do you haveanything to say (which you will have to say)? 你有什么要说的吗?
2) 不及物动词不定式:由于不定式跟中心词有动宾关系,因此不及物动词或短语之后应该使用相应的介词。
She has a room tolive in.她有一间房子住。 He has a child to take care of.他有一个孩子要照管。
3) 有些名词接不定式做定语,可以省略介词,它们是:place, reason, time, way等。
Is that the way to do it (inwhich/that it can be done)? 这是做这个事情的方法吗?
You need a place to sleep (where/inwhich you can sleep).你需要一个睡觉的地方。
不定式是一种非限定性动词。而非限定动词是指那些在句中不能单独充当谓语的动词,可分为不定式,动名词,现在分词和过去分词。
2.用途:
在句中不能作谓语。它具有动词的性质,本身可以带宾语和状语。
【动词不定式】
1.定义:动词 + 不定式
2.用途:
动词不定式在句中可以作句子任何成分。动词不定式的被动形式除了一般形式外还有其完成式和进行式。
[编辑本段][动词不定式的时态、语态]
动词不定式可以作以上各种成分,但它毕竟是动词,所以有动词的属性
动词不定式及其短语还可以有自己的宾语、状语,虽然动词不定式在语法上没有表面上的直接主语,但它表达的意义是动作,这一动作一定由使动者发出。这一使动者我们称之为 逻辑主语,其形式如下:
主动形式 被动形式
一般式 (not) to make (not) to be made
完成式 (not) to have made (not) to have been made
进行式 (not) to be making
完成进行式 (not) to have been making
(1)语态
如果动词不定式的逻辑主语是这个不定式所表示的动作的承受者,不定式一般要用被动语态形式。如:
It's a great honour to be invited to Mary's birthday party.(不定式作主语)
It was impossible for lost time to be made up.(不定式作主语)
I wish to be sent to work in the country.(不定式作宾语)
Can you tell me which is the car to be repaired?(不定式作定语)
He went to the hospital to be examined.(不定式作状语)
在There be结构中,修饰主语的不定式可用被动,也可用主动。如:There are still many things to t ake care of (to be taken care of).但有时两种形式表达的意思不同,如:These is nothing to do now.( We have nothing to do now.) There is nothing to be done now.(We can do nothing now.)
(2)时态
1) 现在时:一般现在时表示的动词,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。
He seems to know this.
I hope to see you again. = I hope that I'll see you again. 我希望再见到你。
2) 完成时:表示的动作发生在谓语动词表示的动作之前。
I'm sorry to have given you so much trouble.
He seems to have caught a cold.
3) 进行时: 表示动作正在进行,与谓语动词表示的动作同时发生。
He seems to be eating something.
4) 完成进行时:
She is known to have been wreaking on the problem for many years.
[编辑本段][疑问词+不定式结构]
疑问词who,what,which,when,where,whether,how后可接不定式构成不定式短语,在句中作主语、宾语、表 语等。如:
①When to leave for London has not been decided yet. (不定式在句子中做主语)
②Mr. Smith didn't know whether to leave or stay there. (不定式在句子中做宾语)
③I asked Professor Xu how to learn English well. (不定式在句子中做间接宾语)
④The question was where to get the medicine needed. (不定式在句子中表语)
以上例句中疑问词+不定式部分,均可转换为相应的从句形式。如:①When we shall leave…③…how I
could learn…
经常在这种结构中使用的动词有:consider,decide,discover,explain,find out,forget,hear,know,lea rn,observe,understand,wonder等。
[编辑本段][动词不定式的语法功能]
一、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
2。"不定式没有人称和数的变化" 意味着不定式的形式不受人称(I,you, she, he, it, they等)的变化而改变,即不管主语是I, you, he, they等,不定式永远不变。同时,也不管单数还是复数,也不改变。如:
I/We/They want to go there tomorrow.
3。当然没有“人称”和“数”的变化,但是却有时态的变化,如to be working, to have worked等,以后你会学习的。