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動詞不定式

來源:大家論壇 發布日期:2011-05-25 15:30

動詞不定式


1. 不定式的基本形式與結構
動詞不定式指通常由 to 加上動詞原形(如 ro write )所構成的一種非限定性動詞形式,但在有些情況下 to 可以省略。動詞不定式有進行體和完成體(如 to be writing, to have written )也有被動態(如 to be write ),所有的主動詞,不論是及物動詞還是不及物動詞,也不論是動作動詞還是狀態動詞,都有不定式形態。助動詞除 be 和 have 外,沒有不定式形式。動詞不定式在語法功能上可作主語、賓語、表語、定語和狀語。
2. 不定式的用法
1 )不定式結構作主語
To get contact with family in Taiwan made him extremely happy since they separated more than 40 years ago.
To finish that task in such a short time is really a challenge.
在上述情況下,如果不定式較長,顯得頭重腳輕,則可由代詞 it 作形式主語(形式主語 it 不可由 that 或 this 等其他代詞代替),而將不定式放在后面。如:
It made him extremaly happy to get contact with his family in Taiwan since they separated more than 40 years ago.
John admitted that it is always difficult for him to be on time.
不定式結構所表示的動作是誰做的,即不定式的邏輯主語,通?梢酝ㄟ^ for sb.to do sth. 結構表達。
It is quite important for us to read good books during a general review.
It is not difficult f or those talented students to pass the exam.
在某些形容詞(如: careless, clever, considerate, foolish, good, impolite, kind, naughty, nice, silly, stupid 等)作表語時,不定式后可以加 of 來引導出其邏輯主語:
It is very kind of you to tell me the truth.
It is stupid of him to do such a silly thing.
2 )不定式作賓語
不定式作賓語有兩種:一種是及物動詞后直接跟帶 to 的不定式,另一種是 “ 及物動詞 + 疑問句 + 帶 to 的不定式 ” 。
及物動詞 + 帶 to 的不定式結構: 只能跟動詞不定式的動詞,常見的有:
afford, agree, aim, appear, ask, believe,?care, claim, ecide,demand,desire,determine,expect,fail,happen,hesitate,hope,intend,learn,long,manage,offer,pretend,promise,prepare,refuse,seek,sweat,
undertake,want,wish 等。(須記。 He managed to solve the complicated problem
The stranger offered to show me the way.
Mr.Smith undertook to build a new plant in South Africa.
動詞 + 疑問代(副)詞 + 不定式:這類動詞常見的有: advise, decide, discuss, find out, forget, inquire ,know, learn, regard, remember, see, teach, tell, understand, wonder 等。常用的疑問代(副)詞有 what, when, where, which, how, whether 等,但不包括 why 。
He does not know when to start.
You can decide whether to continue or to stop.
I will show you how to deal with it.
有時,不定式可由 it 代替,而把不定式放到后面去。這可以用這一結構表達:動詞(如 find, think, consider, feel 等) +it+ 形容詞 + 不定式。
She considers it necessary to make friends with them.
We find it difficult to finish all the homework before 9 o'clock.
 

3 )不定式作表語
一般情況為主語是不定式(表示條件),表詞也是不定式(表示結果):
To see is to believe. To work means to earn a living.
另一種情況為主語是 aim, duty, hope, idea, job, plan, problem, purpose, thing, wish 等名詞為中心的短語,或以 what 引導的名詞性從句,不定式表語對主語起補充說明作用:
His aim is to study abroad in the near future.
The most important thing is to negotiate with them about the problem.
What I want to say is to forget all the unhappy experience.
4 )不定式作定語
不定式結構作名詞詞組修飾語主要有三種類型:
第一種,被修飾的名詞詞組是不定式的邏輯賓語。例如:
There was really nothing to fear. He gave me an interesting book to read.
如果不定式是不及物動詞,后面就得加相應的介詞。例如:
Mary needs a friend to play with. That girl has nothing to worry about.
They have a strict teacher to listen to .
Although the film had been on for ten minutes, I still was not able to find a chair to sit on.
第二種,被修飾的名詞詞組是不定式的邏輯主語。例如:
Have you got a key to unlock door?
The action to be taken is correct.
There is nothing to be gained by pretending.
第三種,被修飾的名詞詞組是不定式的同位結構。這類名詞通常是表示企圖、努力、傾向、目的、愿望、打算、能力、意向等意義的名詞,如 ability, attempt, effort, impulse, inclination, wish 等。例如:
Her daughter will make an even bigger effort to please her.
I have no wish to quarrel with you.
Neither of them had any inclination to do business with Mary.
( 5 )不定式作狀語
不定式結構在句中作狀語通常都能轉換為限制性狀語從句。例如作原因狀語:
They are quite surprised to see the great changes taking place in the area.
=They are quite surprised because they see the great changes taking place in the area.
He was lucky to arrive before dark.
作目的狀語:
She raised her voice to be heard better. =She raised her voice so that she could be heard better.
We went via Heidelberg to miss the traffic jam.
=We went via Heidelberg so that we could miss the fraffic jam.
作結果狀語:
The French football team played so successfully that they even defeated the Brazilians.
He got to the station only to be told the train had gone.
=He got to the station and was told that the train had gone.
3. 不帶 to 的不定式的使用
動詞不定式通常帶 to ,但有些搭配中不帶 to ,在另一些搭配中可帶 to 可不帶 to 。歸納起來,以下情況下使用不帶 to 不定式:
1 )在 can/could, may/might, will/would, shall/should, must, need, dare 等情態動詞之后,動詞不定式不帶 to 。
2 )在表示感覺意義的動詞,如 see, feel, watch, notice, smell, hear, observe 等后,或是表示 “ 致使 ” 意義的動詞,如 have, let, make 等后,動詞不定式不帶 to 。例如: I often heard him say that he would study hard.
I must have him see his own mistakes.
但是,當這類結構轉移為被動語態時,后面的不帶 to 不定式一般轉換為帶 to 不定式。
例如: He was often heard to say that be would study hard.
After he had finished the speaking, he was made to answer innumerable questions.
3 )在動詞 help 之后可用不帶 to 和不定式,也可用帶 to 的不定式。例如:
help the old lady(to)carry the heavy box.
4 )在 had better, would rather, may/might as well, rather than, cannot but 等搭配之后,動詞不定式也不帶 to 。例如:
Unless you feel too ill to go out, I would rather not stay at home tonight.
She could not but criticize his foolish behaviour.
5 )在 make do, make believe, let drop, let fall, let fly, let slip, let drive, let go off, hear, say, hear tell, leave go of 等固定搭配中,用不帶 to 的動詞不定式。例如:
They let go off the rope 。他們松開了繩子。
John let fly a torrent of abuse at me 。約翰朝我痛罵了一頓。
I've heard tell of him 。我聽說過他。
Some of the faculty were let go for lack of the students. 由于生源不足,一些教職員工被解雇了。
6 )在介詞 but, except 之后,如果其前有動詞 do 的某種形式,其后不定式一般不帶 to ,反之則必須帶 to ,表示 “ 不得不,只能 ” 。例如:
He will do anything except work on the farm.
There was nothing left for the enemy to do but surrender.
The spy was both hungry and cold; there was nothing left for him but to give in.
I had no choice but to wait till it stopped raining.
下面一些短語是固定搭配,不帶 to :
can not help but, can not choose but, can not but, do nothing but, have nothing to do but 。例如:
I can not but admire his courage.
如果上述句中有 do , to 省略:
I did nothing but watch TV last night.
如果是下面一個固定搭配,就帶 to :
I have no choice but to give up my idea.

7 )緊跟在 why 或 why not 之后的動詞不定式總是不帶 to 。但是,緊跟 who, what,
which, whether 等連接詞后的不定式帶 to 。例如:
Why stand up if you can sit down?
Why not ask your teacher when you don't understand the meaning?
You needn ' t decide yet whether to study arts or science.
4 不定式的完成式和進行式
1 )構成
完成式: to+have done
進行式: to+be doing
2 )用法
完成式:如果不定式所表示的動作(狀態)發生在主要謂語動作之前,那么不定式就要用其完成式。
進行式:如果主要謂語動作(情況)發生時,不定式所表示的動作正在發生,那么不定式就要用其進行式。例如: She feels relaxed to have finished writing her thesis before the deadline.
The Vikings are believed to have discovered America.
When you called me last night, I happened to be working on the computer.
5. 不定式的被動形式
當不定式的邏輯主語是動作的承受者時,不定式要用被動形式,包括它的一般式和完成式。例如:
The snow was supposed to have blown off the mountain.
6. 不定式的否定形式
否定形式是在不定式的標志 to 前加 not 。例如:
I decided not to ask him again.
Please remember not to leave the lights on when are out.

  

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