第二讲     不定式的基本用法

                                                               

                                                主讲：陈春华

一、感受不定式

1. 观察下列句子，你发现了么问题了吗？

1) He decided work harder in order to catch up with the others.

2) Give up smoking is right.

3) He ask me accomplish the task before Friday.

4) There is nothing worry about.

 

2. 观察下列各句，在不定式或不定式短语下划线，并判断其句法功能：

1).We eat to live，but not live to eat．

2).I have come to hand you a letter．

3) We spend money to have a good time，but not to suffer．

4) He is the young man to marry Lilian．

5) It would be better for you not to tell him the truth now.

6) I tried to defeat him，but only to be defeated.

7) Frequently, the cheapest place to borrow money in the US is a credit union(信用会)。

8) You must keep the promise to pay my money within a month.

9) I am not such a fool as to believe that.

10) He went to the sea side only to be drowned.

11) They seem to be quarrelling.

12) Allow me to introduce Mr. White to you.

13) He wants to organize a company.

14) His plan was to set up a big company．

15) My father gave me three choices：to go to college，to do business，to get married．

 

小节一：

不定式的形式及其句法功能如下下表所示：

 

 

二、不定式的特点

1、有动词的特点。

1）不定式有语态的变化：

He wants to be respected ，but hates to respect others．

I tried to defeat him，but only to be defeated ．

2）不定式可表示时间， 故有时态的变化：

观察下列句子：

He seems（or appears，is said，is believed）to study English．

He seems to be studying English

He seems to have studied English．

They seem to have known about the news.

I happened to be waiting for the bus when the accident happened.

小节二：

不定式的时态、语态形式及其句法功能：

 

 

三、不定式可以有意义上的主语：

观察下列各句：

To learn music is difficult．（意义上的主语未说出，不知是谁学音乐。）

For me to learn music is difficult．（指出是我学）

His purpose is to learn music．（可能是他学）

His purpose is for his son to learn music．（他的儿子学音乐）

There is nothing to eat．（不知给谁吃）

There is nothing for you to eat．（给你吃）

He saves his money to spend on books．（可能是他自己花）

He saves his money for his brother to spend on books．（他的弟弟花）

小节三：

不定式意义上的主语由介词for引出：

观察下列各句：

1)       It is so nice of you to help me with my math.

2)       It is impolite of you to visit someone without telling him in advance.

小节四：

不定式意义上的主语由介词for引出：

注意：

It is + necessary (important, hard, difficult, easy, impossible etc.) + for sb. to do ….

It is + nice ( good, clever, bright, wise, fool, stupid, foolish, silly, rude, careless, etc.) + of sb. to do

 

四、不定式使用时应该注意的几个问题：　

１在用作主语时，不定式常常被放到句尾，前面用it代替它：

It is difficult to know oneself．

It is not always easy to tell a lie．

It won't hurt you to stay here a day or two．

It requires a lot of money to build a house．

It is impossible for one to know everything．（带有意义上的主语）

２．不定式作及物动词的宾语

　不定式可用作及物动词的宾语。常见的有：choose, help，hope，ask，refuse，decide，promise，wish，pretend，expect，arrange，learn，plan，attempt，dare，manage，agree，prepare，fail，determine，offer，choose，desire，elect，long，(happen，seem)，等等。　

He wishes to go there．　　　　　　　　John decided to marry her．

I cannot afford to get sick．　　　　　　　She promised to bring her book to me．

They sought to kill their enemy．　　　　　He needed to be admired．（被动不定式）

３．“疑问词+不定式”作及物动词的宾语

有些及物动词可以用不定式作宾语，但不定式需加一个疑问词。这种带疑问词的不定式可以看作是疑问词引起的从句的简短形式.

I cannot tell what to do（=tell what I must do）．

I wonder where to buy it（=wonder where I can buy it）．

Do you know when to start?(=when we should start)

I don't know whether to laugh or to get angry（=know whether I should laugh or get angry）．

4．不定式作宾补动词的宾语

不定式可用作宾补动词的宾语，这时不定式先由it代替，同时移到句尾（或从句末尾）。这种不定式通常可以变为一个由that引起的从句。常这类动词有：make, think, feel, find, believe,consider…

I thought it good to wait（=that I should wait）there．

She judges it useless to be quarrelling（=that any one should be quarrelling）with him．

I make it a rule to get up at five．

He believed it his duty to tell you the secret．

I found it necessary to keep silent about this．

5.用在宾补动词后作宾语补足语。

 1)感官动词 see, watch, observe, notice, look at, hear, listen to, smell, taste, feel + 不带的to不定式。  

表示动作的完整性，真实性；

　I saw him work in the garden yesterday.   　昨天我看见他在花园里干活了。(强调"我看见了"这个事实)

 比较：　He was seen to work in the garden yesterday.

 2) 使役动词   have ，make， let 等词后不定式要省略to, 但同1)一样被动以后要还原to

I ‘d like to have John do it.

Paul doesn’t have to be made to learn.

3) 有些动词后跟带不定式作宾语补足语。如：want，wish， promise，expect，allow,  cause  permit, enable， tell, remind, ask, beg, invite, order, intend, teach, warn, persuade, dare, advise, encourage, require

语法针对性练习：用动词的适当形式填空：

1）. While she lived , her front gate was always locked and no one ever saw her ___ (leave ) or saw anybody ____ ( go ) in .

2) . I tried _____ (persuade ) him ___ ( agree) with your proposal .

3). she rushed out of the room without giving me a chance _____ ( explain).

4) . ---- Did you remember ______(lock ) the door ?

   ----- No, I didn’t . I’d better go back and _______ ( do ) it .

5) .The baby needs _______ ( look ) after .

6) . He is said ________ ( send ) to hospital already .

7) . The library assistant doesn’t allow the magazines _____ ( take ) away .

8) . Would you like _____ ( go ) with me or would you rather _____ ( stay )at home ?

9) .He was ever so happy ________ ( admit ) to the army .

10) .The thief happened ________ ( quarrel ) about the treasures when the police went in .

11) . I hope ___________ ( invite ) to the party .

12) .They don’t allow these books ________ ( take ) out of the reading room .

13) . He pretended ________( read ) the book before .

14) . We had no choice but _________( do ) what we were asked .

15) . The Prime Minister is said __________( speak ) on TV tonight .

16 ) . Before he let us ____ ( go ) he made us _________( promise ) _____ ( not tell ) anyone what we had seen .

17) . I expect ________ ( finish ) the work by the end of next month .

18) . I happened _________ ( stand ) next to him when he collapsed .

19) . You had better _______( not wake ) me up when you come in .

20) .She would rather stay at home than ______ ( go ) out at night .

21) . I think it important ________( do ) so .

22) . They did all they could ______ ( save ) the child .

23) . Why _________ ( not report ) to the police when the accident happens ?

24) . I have something important ______ ( tell ) you .

25) . I am glad _______ ( work ) with you now .