动词不定式用法 经典例句总结 下载本文

作表语

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. ②My chief purpose is to point out the difficulties of the matter. ③What I would suggest is to put off the meeting.

当主语和表语都是不定式时,其含义一是条件,一是结果(例①)。当主语是aim,duty,hope,idea,mista ke,plan,purpose,suggestion等为中心词的名词词组(例②)时,或以what引导的名词性分句(例③),不定 式说明主语的内容。

④Our work is serving the people.

⑤What he likes is taking a walk after supper. ⑥The story told by Mr.Wang is interesting.

④⑤句动名词作表语,与主语部分可以转换,如Serving thepeople is our work,而⑥句中是现在分词作表语,说明主语的性质、状态,现在分词具有形容词的各种特征,另外,动名词作表语还应与进行时态区别开来。

作状语

(1)目的状语

To… only to (仅仅为了), in order to, so as to, so(such)… as to… (如此……以便……) 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,表事先没有预料到的,要放在句子后面。 What have I said to make you angry. He searched the room only to find nothing. (3) 表原因 I'm glad to see you. 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

答案:B. 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,常位于“形容词+动词不定式”结构的末尾。

作定语

⒈不定式作定语

不定式在句中作定语,置于被修饰的名词或代词之后。如: ①The next train to arrive is from Washington. ②Do you have anything to be taken to your sister? ③Do you have anything to say on the question? ④Would you please give me some paper to write on? ⑤My wish to visit France has come true at last. 不定式短语作定语和被修饰词之间表示以下关系: (1)表示将来的动作(例①)。

(2)与被修饰词之间有动宾关系,如是不及物动词,则需加介词(例④)。

(3)与被修饰词之间有动宾关系,同时与句中其它词之间又有逻辑上的主谓关系时,尽管有被动含义,却仍 用主动语态(例③);如只有动宾关系,而无逻辑上的主谓关系,则需用被动语态(例②)。

(4)不定式作定语时,一般可转换为定语从句,例①to arrive=that will arrive。

相关省略

(1)情态动词( 除ought 外,ought to意思是“应该”,是情态动词,只有一种形式,后边接动词不定式,to不能省略。ought to没有人称和数的变化,后接动词原形可以表示现在、将来或过去将来,由时间状语或上下文决定。例如:

They ought to come tomorrow.他们明天应当来): (2)使役动词let,have,make:

(3)感官动词see,watch,look at,notice,observe,hear,listen to,smell,feel,find 等后作宾补,省略to。 注意:在被动语态中则to 不能省掉。 在使役动词中get除外(get sb. to do sth.) 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.

(4) 表示个人意愿或倾向的would rather,had better,might(just) as well:rather than置于句首时。 Rather than ride on a crowded bus,he always prefers to ride a bike. (5) Why… / why not…:

(6) help 可带to,也可不带to,help sb (to) do sth:

(7) but和except:but前是动词do时,后面出现的动词用不带to的动词不定式。 (8) 由and,or和than连接的两个不定式,第二个to 可以省去:

(9) 通常在discover,imagine,suppose,think,understand等词后,可以省去to be: He is supposed (to be) nice. 他应该是个好人。

(10)but作介词,后接不定式结构时,前面谓语动词部分若含有do的形式时,but后的不定式要省去to,否则要带to。

He wants to do nothing but go out.

He wants to believe anything but to take the medicine.

(11)当两个或多个不定时短语由连词and,but或or连接时,后一个或几个不定式符号to常省略。但若表示对比、对照关系时,则不能省略。

He wants to move to France and marry the girl.

The purpose of new technologies is to make life easier,not to make it more difficult.

(12)不定式做表语时,一般要带to,但若主语部分中含有do的各种形式时,符号to可省去。 We've missed the last bus.All we could do now is walk home.

否定式

Tell him not to shut the window…

She pretended not to see me when I passed by. 我走过的时候,她假装没看见。

特殊句型

so as to

(1) 表示目的;它的否定式是so as not to do。

Tom 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) so kind as to ——劳驾

Would you be so kind as to tell me the time?劳驾,现在几点了。 2、 \动词原形\表达向某人提出建议 \为什么不……?\干吗不……?\ 例如:

Why not take a holiday? 干吗不去度假?

3、It's for sb.和 It's of sb.

(1)for sb. 常用于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:

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的句型一般用表示人物的性格,品德,表示主观感情或态度的形容词,如good,kind,nice,clever,foolish,right。

It's very nice of you to help me. 你来帮助我,你真是太好了。 for 与of 的辨别方法:

用介词后面的代词作主语,用介词前边的形容词作表语,造个句子。如果道理上通顺用of,不通则用for。如: You are nice. (通顺,所以应用of)。

He is hard. (人是困难的,不通,因此应用for。) 4、不定式的特殊句型too…to… (1)too…to 太…以至于…

He is too excited to speak.他太激动了,说不出话来。 ——Can I help you 需要我帮忙吗

——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。谢谢您。

(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”。 It's never too late to mend. (谚语) 改过不嫌晚。

(3) 当too 前面有only,all,but时,意思是:非常… 等于very。 I'm only too pleased to be able to help you. 我非常高兴能帮助你。 He was but too eager to get home. 他非常想回家。

相互区别

不定式与介词\区别

to 有两种用法: 一为不定式+动词原形;

一为介词+名词动名词,to 在下面的用法中是第二种,即to+ 名词/动名词:

admit to承认,confess to承认,be accustomed to 习惯于,be used to 习惯于, stick to 坚持, turn to开始,着手于, devote oneself to 献身于, be devoted to 致力于, look forward to 盼望,pay attention to 注意

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 solders had no choice but to give in. On Sunday afternoon I had nothing to do but watch TV.

区别联系

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 接不定式或动名词,意义相同 3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:The students are starting to work on the difficult 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/us swimming in the lake. Our teachers don't permit us to swim in the lake.

4 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 to 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.

语义不同

目录

1 stop to do(停现在做的去做另一件事) stop doing(停止正在做某事) 2 forget to do(忘记去做某事) forget doing(忘记做了某事)

3 remember to do(记得要去做某事) remember doing(记得做过某事) 4 regret to do(遗憾做某事) regret doing(遗憾做了某事)