動詞不定式(The Infinitive)

動詞不定式：（to）+ do，具有名詞、形容詞、副詞的特征。

一、不定式的形式：

主 動 被 動

一般式 to do to be done

進行式 to be doing /

完成式 to have done to have been done

完成進行式 to have been doing /

否定式：not /never + (to) do

二、不定式的句法功能：

1.作主語：

eg.)To make a speech here is an honor.

To lose heart means failure.

動詞不定式短語作主語時，常用形式主語it作形式主語，如上兩句可用如下形式：

It is an honor to make a speech here.

It means failure to lose heart.

常用結(jié)構(gòu)：

It+be+ adj./n.+ for sb. to do sth.

It+be+ adj. + of sb. to do sth. =sb. be + adj. + to do sth.

(常見形容詞:clever, silly, foolish, stupid, wise, kind, rude, impolite, careless, cruel, crazy, etc.)

Eg.)It’s necessary for us to have a good knowledge of English.

It is foolish of you to make such a mistake.=You are foolish to make such a mistake.

2.作表語：

eg.)Her wish is to become a novelist.

He appears to have caught a cold.

不定式一般緊跟在系動詞如be, seem, remain, appear等后面,用來說明主語的內(nèi)容。這類結(jié)構(gòu)中的主語一般為名詞，如：idea, purpose, hope, plan, intention, wish, dream, etc.

eg.) My purpose is to teach them a lesson.

有時句子主語也可以是不定式或名詞性從句。

Eg.) To be strict with students is to be responsible to them.

What I want to do is (to )tell you the truth.

如果主語中含有do的任何形式, 那么不定式可以省去to.

Eg.) The only thing he could do was ( to) tell the truth.

比較:

A組: Sth.+be +不定式(作表語)---表示主語的具體內(nèi)容

Sth.+be +不定式(作表語)---表示時態(tài)(將來時)

Eg.)He is to tidy up the room.

His plan is to tidy up the room.

B組:動名詞和不定式在句中作表語的區(qū)別:

1. 一般情況下,區(qū)別不大,可通用

eg.) Seeing is believing.

=To see is to believe.

2. 動名詞表示的動作較抽象、或是習慣性的, 而不定式表示某次具體的動作.

Eg.)My job is typing papers.

My job now is to type these papers.

3.作賓語：

A. 動詞+ to不定式

常見動詞: hope, wish, long, want, refuse, pretend, promise, agree, aim, decide, expect, offer, fail, plan, learn, manage, intend, desire, etc.

eg.) I longed to become an artist.

He helped (to) bring up the orphan.

B.動詞+(間接賓語)+疑問詞+ to不定式

常見動詞: know, decide, wonder, learn, remember, understand, find out, etc.

eg.) I don’t know what to say to comfort her.

The farmer showed us how to milk the cow.

C.動詞+ it+賓語補足語+( for sb.)+ to不定式：

常見動詞:find, consider, think, make, feel, etc.

eg.) Marx found it important to study the situation in Russia.

I think it important for you to recite some English articles.

D.介詞but, except后可接to不定式作賓語。

注意句中謂語或非謂語部分含有do，那么不定式可省去to

eg.)Seeing the room crowded, I had no choice but to stand in the dark.

Seeing the room crowded, I could do nothing but stand in the dark.

4.作賓語補足語：

A. 動詞/動詞詞組+賓語+to不定式

常見動詞: want, wish, ask, tell, order, beg, allow, permit, help, advise, persuade, cause, force, warn, invite, urge, encourage, prepare, call on, would like, wait for, etc.

eg.)I got them to join us in the discussion.

They are waiting for the school bus to come.

B. 動詞+賓語+不帶to的不定式

常用動詞: feel (一感) ; hear, listen to(二聽); make, let, have(三讓); see, watch, observe, notice, look at(五看) ;help (半幫助,可帶to或不帶to)etc. 但改為被動語態(tài)時，不定式要加to.

Eg.) I saw him cross the road.

He was seen to cross the road.

比較: I saw him crossing the road.

He was seen _____the road.

I saw him carried downstairs.

He was seen ____ downstairs.

5.作定語：(考點集中在動詞不定式與被修飾詞的邏輯關(guān)系的判斷上)

A.與被修飾名詞構(gòu)成動賓關(guān)系：

Eg.) I have a meeting to attend.

He found a good house to live in. (如果不定式是vi，其后應(yīng)有適當?shù)慕樵~.)

如果不定式修飾time, place, way，可以省略介詞：

eg.)He has no place to live.

This is the best way to work out this problem.

注意如果句子的主語不是不定式的邏輯主語,不定式就用被動語態(tài)表示。比較:

I am going to the post office, for I have a letter to post.

I am going to the post office, do you have any letter to be posted?

B. 與被修飾名詞構(gòu)成主謂關(guān)系：

Eg.)He is the right person to do that job.

He is the first to get here.

注意不定式+介詞修飾名詞也可以轉(zhuǎn)換成介詞+關(guān)系代詞（whom或which）+不定式。

Eg.) Mary is a nice companion to travel with.

Mary is a nice companion with whom to travel.

I got a piece of paper to write on.

I got a piece of paper on which to write.

C．說明所修飾名詞的內(nèi)容：

Eg.) We have made a plan to finish the work.

Jane expressed a wish to earn her own living.

6.作狀語：

A.表目的：

Eg.) He worked day and night to pay off the debt .

She sold her hair to buy the watch chain.

注意不定式邏輯主語與句子主語要一致：

To save money, every means has been tried. (×)

To save money, he has tried every means. (√)

= He has tried every means in order to/so as to save money.

= In order to save money, he has tried every means.

B.表結(jié)果：

Eg.)I visited him only to find him out.

Would you be so kind as to tell me the way to the garden Hotel?

His behavior is such as to make his friends angry.

The patient is strong enough to walk about.

too…to…結(jié)構(gòu)

Eg.)It’s too dark for us to see anything.

The question is too simple for him to answer.

注：對少數(shù)幾個表示心情或傾向的形容詞，如：glad, ready, pleased, willing, anxious, happy, satisfied, etc.用于too…to…結(jié)構(gòu)時表示肯定意義。

eg.)They were too anxious to leave.

I am only/but too glad to do you the favor.

C.表原因：

Eg.)They were very excited to hear the news that their team had won the game.

7.作插入語和同位語：

常見插入語:to tell (you) the truth/to be frank; truth to tell實不相瞞;to start/begin with; to conclude; to make matter worse; to be more exact確切地講;to make a long story short長話短說，簡而言之;to be fair公平地說，憑心而論;to be sure肯定地，毫無疑問地;

eg.)To tell (you) the truth, I don’t like the way _______he talked.

To make matter worse/___ ____, the computer broke down.

We have made a plan to finish the work.

Her wish to be an air hostess has never come true.

三、不定式的時態(tài):

1.一般式－(to)+動原：不定式的一般式所表示的動作或狀態(tài)與謂語動詞動作同時發(fā)生或發(fā)生在謂語動詞動作之后。

Eg.)The policeman made the thief stand in the corner.

The play is said to be made into a film soon.

2.進行式－to be+現(xiàn)分：不定式的進行式所表示的動作或狀態(tài)與謂語動詞動作同時發(fā)生。(seem, appear, happen, pretend等動詞的結(jié)構(gòu)中)

Eg.)The boy pretended to be working hard.

=The boy pretended that he was working hard.

He seems to be reading in his study.

=It seems that he is reading in his study.

3.完成式－to have +過分：不定式的完成式表示的動作或狀態(tài)發(fā)生在謂語動詞動作之前.

eg.)I regretted to have told a lie.

I happened to have seen the film.

The novel is said to have been translated into several foreign languages.

=It is said that the novel has been translated into several foreign languages.

比較: I must be off now. I am pleased to have met/meeting you all.(分手告別時)

Pleased to meet you, Mr. Cook.(初次見面時)

四、不定式的語態(tài):

主動式和被動式

A. 如不定式的邏輯主語是動作的承受者, 不定式需用被動語態(tài)－to be +過分

eg.) He dislikes to be praised in public.

The only animal to be seen in the desert was the camel.

B. 主動的形式表示被動:

①句中存在不定式的邏輯主語, 構(gòu)成邏輯上的主謂關(guān)系：

eg.) The master gave his dog a few bones to eat.

I have a lot of papers to type.

(比較:I am free now. Do you have any papers to be typed?)

②在“形容詞+不定式”結(jié)構(gòu)中, 如不定式與句子主語構(gòu)成邏輯上的動賓關(guān)系,那么不定式多用主動語態(tài).

常見形容詞：hard, difficult, easy, fit, cheap, expensive, interesting, etc.

Eg.) The water is fit to drink.

The couch is comfortable to sit on.=It is comfortable to sit on the couch.

The sentence is easy _____ (explain). =It is________

The tea is bitter _______(taste).

③在there be結(jié)構(gòu)中,傾向于用不定式主動語態(tài)表示被動意義.

Eg.) There is always much work to do in the house.

④下列句子慣用不定式主動語態(tài).

Eg.) The house is to let/to be let. 這房子待出租。

He is not to blame. 他不該受責備。

但在be + to不定式以及be likely to結(jié)構(gòu)中，如果主語是不定式所表示的承受者，那么不定式仍須用被動語態(tài)。

Eg.) The collection of poems is to be published within a year.

The results of the exams remain to be seen.

He is likely to be made monitor of our class.=It is likely that he is made ….

五、不定式的否定式： not/never + (to ) 不定式

eg.) They hurried along in order not to be late.

The boy promised never to play truant again.

六、不定式的省略與保留：保留to,省略do動詞。

Ⅰ.不定式符號的省略與保留:

1. 在had better, would rather, would rather…than…, would sooner…than…, cannot but, why (not) 等結(jié)構(gòu)后面的不定式符號to通常被省略。如:

eg.) You’d better tell her the truth.

2. 動詞不定式短語作介詞but, except, besides的賓語，且介詞之前有行為動詞do或其它形式時，不定式符號to通常被省略。

Eg.) What do you like to do besides swim?

My mother could do nothing but wait for the doctor to arrive.

Now he had given himself no choice but to tell her.

3. 兩個或多個不定式短語表示并列關(guān)系時，后面不定式短語的不定式符號to通常被省略；如果表示對比關(guān)系，則不定式符號to通常保留。

eg.) They didn’t tell me whether to go on or to stop. （對比關(guān)系）

She told the child to stay there and wait till she came back. （并列關(guān)系）

4．在某些感官動詞或使役動詞（如：hear，listen to， notice，observe， see， watch， make等）之后充當賓語補足語

的不定式中，不定式符號to總是被省略， 但在被動語態(tài)的句子中，不定式符號to通常保留。

Eg.) They made that man work all the morning.

That man was made to work all the morning.

5.不定式短語作表語，不定式符號to通常保留，但當what引導的名詞性從句作主語，或all，everything等后接定語從句作主語，從句謂語部分含有動詞do 或do的其他形式時，作表語的不定式可以保留也可省略不定式符號to。

eg.) The greatest happiness is to work for the happiness of all.

The only thing I can do is (to) go on y myself.

II.不定式符號后面動詞的省略與保留

1.為了避免重復，在hope， wish， want， like， love，decide， mean， prefer， have to， be able to， be going to， used to， ought to等動詞及習語后面出現(xiàn)與上文相同的不定式時，常保留不定式符號to，而把其它部分省略。

Eg.) Ms King lied to us because she had to.

2.當不定式在ask, advise, persuade, wish, allow, permit, tell, expect, force, invite, beg等動詞后面充當賓語補足語時, 為了避免重復, 常保留不定式符號to，而把后面的動詞省略.

eg.) She wants to come , but her parents won’t allow her to.

If he doesn’t want to go there, don’t force him to.

He didn’t come, though we had invited him to.

3.在特定的上下文中, 為了避免重復, 如果不定式為一般式to be…或完成式to have done時, 則不定式符號to和be或have常一并保留, be或have之后的部分通常要省略.

eg.) ---Aren’t you the headmaster?

--- No, but I don’t want to be.

--- Hasn’t he finished the report?

--- No, but he ought to have.

補充:

不定式符號后面動詞的省略與保留：

Eg.)1. If you don’t want to do it, you don’t need to.

2.---Ought I to finish the work today?

---Yes, you ought to.

注：㈠以上例句中的不定式符號to均不能省略。但如省略名詞后的不定式時，則to可以一起省去。

Eg.) Never will Tom miss school for no reason; he hasn’t the courage (to).

I will come as soon as I have got the chance (to).

㈡ want 和would like如用于從句中，to通常可以省略。

Eg.) Come whenever you want (to).

You can stay here as long as you like (to).

㈢如不定式帶有系動詞be或助動詞have, 則須保留be或have.

Eg.) ---Are you a teacher?---No, but I used to _be_.

--- Sorry, I haven’t finished my work yet?---Well, you ought to have.

㈣另外兩種省略to的情況.

⑴ 如主語部分含有動詞do,則作表語的不定式可省略to

eg.) What I want to do is run a night school.

⑵當兩個或兩個以上的不定式并列使用時,除第一個不定式以外,其余的不定式一般要省略to.

Eg.) It is up to you to decide whether to stay or leave.

He wished to study medicine and become a doctor.