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1. 常见样例

  1. It was impossible for lost time to be made up. (不定式作主语)

  2. I wish to be sent to work in the country. (不定式作宾语)

  3. Can you tell me which is the car to be repaired?(不定式作定语)

  4. My work is to clean the room every day. (不定式作表语)

  5. 如果不定式为不及物动词,其后应有必要的介词。

    The chair looks rather hard, but in fact it is very comfortable to sit on.

2. 语态

  1. 动词和参与此动作的主语之间关系的一个术语。当主语是动作的发起者(或之一)时,称为主动语态。

    It is not easy to learn English well.

  2. 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。

    It’s a great honor 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。

  3. 在 There be 结构中,修饰主语的不定式可用被动,也可用主动。

    There are still many things to take care of (to be taken care of).

    但有时两种形式表达的意思不同。如下

    There is nothing to do now. ( We have nothing to do now.)

    There is nothing to be done now. (We can do nothing now.)

3. 时态

  1. 现在式: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。一般为:动词 + to do something

    He seems to know this.

    他似乎知道这件事

    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。

    I’m sorry to have given you so much trouble.

    He seems to have caught a cold.

  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。

    He seems to be eating something.

  4. 完成进行式

    She is known to have been wreaking on the problem for many years.

一般在表示情绪的动词后加 to do 也表将来。

4. 疑问词

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:

  1. When to leave for London has not been decided yet. (不定式在句子中做主语)
  2. Mister Smith didn’t know whether to leave or stay there. (不定式在句子中做宾语)
  3. I asked Professor Xu how to learn English well. (不定式在句子中做直接宾语)
  4. The 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。

  1. When to leave → When we shall leave

经常在这种结构中使用的动词有:consider, decide, discover, explain, find out, forget, hear, know, learn, observe, understand, wonder 等。

5. 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。

5.1 把不定式置于句首。

To get there by bike will take us half an hour.

骑自行车到那儿将花费我们半个小时。

To make up for lost time is not possible.

要弥补失去的时光是不可能的。

To lean out of the window is dangerous.

身子探出窗外很危险。

To save money now seems impossible.

现在好像不可能存钱。

5.2 用 it 作形式主语

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。

  1. It is + 名词 + to do

    It’s our duty to take good care of the old.

    照顾老人是我们的责任。

    It is an offence to drop litter in the street.

    在马路上乱丢废物是违章的。

  2. It takes somebody + some time + to do

    How long did it take you to finish the work?

    你花了多少时间来完成这项工作?

  3. It + be + 形容词 + for somebody + to do

    It is difficult for us to finish writing the composition in a quarter of an hour.

    我们难以在四分之一小时内完成这篇作文。

    形容词可为:easy, difficult, hard, important, possible, impossible, comfortable, necessary, better

    也可以用一些程度词:the first, the next, the last, the best, too much, too little, not enough

  4. It + be + 形容词 + of somebody + to do

    It is stupid of you to write down everything (that) the teacher says.

    你把老师说的所有东西都记下来的行为是很愚蠢的。

    形容词可为:kind, nice, stupid, rude, clever, foolish, thoughtful, thoughtless, brave, considerate, silly, selfish

  5. It seems (appears) + 形容词 + to do

    It seemed impossible to save money.

  6. It + 不定式结构可位于 believe,consider,discover,expect,find,think 和 wonder 之后

    He thought it would be safer to go by train.

    他认为乘火车比较安全。

    He will find it is hard to make friends.

    他会感觉到交朋友困难。

  7. 不定式的完成式也可作句子的主语

    To have made the same mistake twice was unforgivable.

    两次犯同样的错误是不可原谅的。

    It is better to have loved and lost than never to have loved at all.

    爱过而后失去了爱,比从未爱过要好。

  8. 当不定式作主语的句子中又有一个不定式作表语时,不能用It is… to…的句型

    (对) To see is to believe. 眼见为实。

    (错) It is to believe to see.

补充:在句型 3 中,常用表示客观情况的形容词,如:difficult, easy, hard, important, impossible, necessary 等;在句型 4 中,常用 careless, clever, good, foolish, honest, kind, lazy, nice, right, silly, stupid, wise 等 表示赞扬或批评的词。在句型 3 中不定式前的 somebody,可看作其逻辑主语。这一句式有时相当于 somebody is + 形容词 + to do 句式。

It’s kind of you to help me with my English.(You are kind to help me with my English.)

6. 作宾语

  1. 以下动词后,只能跟不定式作宾语。

    afford (付得起),agree(同意),aim(力求做到),appear(显得),arrange(安排),ask(要求),attempt (试图),care(想要),choose(决定),claim(声称),condescend(屈尊),consent(准许),decide(决定),demand(要求),determine(决心),endeavor(竭力),expect(期待),fail(未履行),help(帮助),hesitate(犹豫),hope(希望),learn(学会),manage(设法),neglect(疏忽),offer(主动提出),plan(计划),prepare(准备),pretend(假装),proceed(接着做),promise(答应),prove(证明),refuse(拒绝),resolve(解决),seem(觉得好像),swear(发誓),tend(往往会),threaten(预示),undertake(承诺),volunteer(自愿做),vow(发誓),want(想要),wish(希望)。举例

    The driver failed to see the other car in time.

    司机没能及时看见另一辆车。

    I happen to know the answer to your question.

    我碰巧知道你那道问题的答案。

  2. 动词 + 疑问词 + 不定式

    动词有 decide,know,consider,forget,learn,remember,show,understand,see,wonder,hear,find out,explain,tell 等

    Please show us how to do that.

    请演示给我们如何去做。

    There are so many kinds of tape-recorders on sale that I can’t make up my mind which to buy.

    有这么多的录音机,我都拿不定主意买哪一种。

    注意:疑问词带不定式在句中作成分时,谓语动词用单数。

    The question is how to put it into practice.

    问题是怎样把它付诸实施。

  3. 当复合宾语中的宾语是不定式时,先用形式宾语 it 代替不定式,把不定式置于补语之后,即:主语 + 动词+ it + 补语 + to do 句式。

    We think it quite important for us to learn a foreign language well.

7. 作补语

7.1 动词 + 宾语 + 不定式(to do)

常见动词:advise,allow,believe,cause,challenge,compel,declare,encourage,forbid,force, find,hire,induce,instruct,invite,like,order,permit,persuade,remind,request,require,select,send,suppose,tell,train,urge 等。

  1. Father will not allow us to play on the street.

    父亲不让我们在街上玩耍。

  2. We believe him to be guilty.

    我们相信他是有罪的。

7.2 to + be 的不定式结构

to + be 的不定式结构,作补语的动词。

常见动词: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。例如

We consider Tom to be one of the best students in our class.

我们认为汤姆是班上最好的学生之一。

7.3 to be + 形容词

常见动词:Seem, appear, be said, be supposed, be believed, be thought, be known, be reported, hope, wish, desire, want, plan, expect, mean 等等。

The book is believed to be uninteresting.

人们认为这本书没什么意思。

7.4 there + 不定式

常见动词:believe, expect, intend, like, love, mean, prefer, want, wish, understand 等等。

We didn’t expect there to be so many people there.

我们没料到会有那么多人在哪里。

7.5 秃头不定式作补语

秃头不定式, 即不带“to”的不定式,其语法功能一般在句子中作宾语的补语(宾语补足语)。

用秃头不定式作宾语补足语的常用动词如下:

口诀:“五看、三使役“,“两听、一感” 要记住,若是 “宾补” 变 “主补”,主补 “to” 字不能无。动词 let 属例外,其宾补/主补 “to” 均无。说明:

五看:see、watch、notice、observe、look at

三使役:have、make、let

两听:hear、listen to

一感:feel

I often see him go to school on foot. (秃头不定式作宾语补足语)

He is often seen to go to school on foot.(不定式作主语补足语,要带 “to”)

Let him try again. (He is let try again.)(let的主补与宾补均用秃头不定式)

7.6 Find 特殊用法

Find 后可用分词做宾补,或先加形式宾语,再加形容词,最后加带 to 的动词不定式。find 后也可带一个从句。此类动词还有 get,have。

I found him lying on the ground.

I found it important to learn.

I found that to learn English is important.

8. 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。

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, mistake, plan, purpose, suggestion 等为中心词的名词词组(例 2),或以 what 引导的名词性分句(例 3)时,不定式说明主语的内容。

  1. To be kind to the enemy is to be cruel to the people.
  2. My chief purpose is to point out the difficulties of the matter.
  3. What I would suggest is to put off the meeting.

2、3 句动名词作表语,与主语部分可以转换,如 Serving the people is our work,而 3 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。

  1. Our work is serving the people.
  2. What he likes is taking a walk after supper.
  3. The story told by Mister Wang is interesting.

9. 作状语

9.1 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。

9.2 结果状语

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.

9.3 表原因

I’m glad to see you.

10. 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。

  1. The next train to arrive is from Washington.
  2. Do you have anything to be taken to your sister?
  3. Do you have anything to say on the question?
  4. Would you please give me some paper to write on?
  5. My 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 1 中 to arrive 可换为 that will arrive。

11. 相关省略

  1. 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。

    They ought to come tomorrow.

    他们明天应当来。

  2. 使役动词 let, have, make 可省略 to

  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。

    在被动语态中则 to 不能省掉。

    I saw him dance.(He was seen to dance.)

  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,to 可省略。

    Rather than ride on a crowded bus, he always prefers to ride a bike.

  5. help 可带 to,也可不带 to, help somebody (to) do something。

  6. 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。

  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, understand 等词后,可以省去 to be

He is supposed (to be) nice. 

他应该是个好人。

  1. 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.

12. 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。

13. 特殊句型

  1. so as to(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。

  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?

  3. It’s for somebody

    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。

  4. It’s of something

    of somebody 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。

  5. 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。

    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)

  6. too … to … (太 … 以至于不能 …)

    He is too excited to speak.

    他太激动了,说不出话来。

    I’m afraid the box is too heavy for you to carry it.

    这箱子太重,恐怕你搬不动。

  7. too … to … 中的 too 之前加否定词,则整个句子用否定句表达肯定。 too 后那个词表达一种委婉含义,意为 “不太”。

    It’s never too late to mend.(改过不嫌晚)

  8. too … to … 中的 too 之前 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。(唯有高兴能够表达)

    He was but too eager to get home.

    他非常想回家。(除了渴望别无他想)

14. 不定式与介词 to 的区别

to 有两种用法:

  1. 不定式 + 动词原形;

  2. 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

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 soldiers had no choice but to give in.

On Sunday afternoon I had nothing to do but watch TV.

15. 动名词与不定式

  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. 在下列情况下,一般要用不定式:

    1. hate, like, love 前有 would(should) 时

      I’d like to have a cup of coffee.

    2. 当谓语动词 begin, continue, start 等是进行式时

      The students are starting to work on the difficult math problem.

    3. begin, continue, start 与 know, understand 等状态动词连用时

      I soon began to understand what was happening.

    4. advise, 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。

      Our teachers don’t permit our/us swimming in the lake.

      Our teachers don’t permit us to swim in the lake.

  3. 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。

    forget, 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。

    Don’t forget to post the letter for me.(未做)

    Have you forgotten meeting her in Beijing Airport?(已做)

    Remember to close the windows before you leave.(未做)

    I remember writing him a letter a year ago.(已写)

    We regret to tell you that all of you are not invited to attend the meeting.(遗憾,正在告诉)

    They regretted ordering these books from abroad.(后悔,已做)

16. 语义不同

  1. stop to do(停下来去做另一件事)

    stop doing(停下正在做的事)

  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)

  5. cease to do(长时间不做某事)

    cease doing(短时间不做某事)

  6. try to do(努力做某事)

    try doing(试着做某事)

  7. go on to do(继续去做某事)

    go on doing(继续做某事)

  8. afraid to do(担心做某事)

    afraid doing(担心正在做的事)

  9. interested to do(对做某事感兴趣)

    interested doing(对正在做的感兴趣)

  10. mean to do(打算做某事)

    mean doing(做某事很有意义)

  11. begin / start to do(开始去做某事)

    begin / start doing(开始做某事)

17. to + 不定式

莎士比亚的作品里面的独白有很多 to + 不定式

to be or not to be, that’s a question.