中考英语助动词和情态动词讲解

中考英语助动词和情态动词讲解

(一)助动词

助动词的特殊用法

1. 协助主要动词构成谓语动词词组的词叫助动词。被协助的动词称作主要动词。助

动词本身没有词义，不可单独使用。

--- I didn’t see her yesterday.

( didn’t是助动词，无词义，see是主要动词，有词义）

2. 助动词(主要是be, do 和have ）协助主要动词完成以下功能，可以用来：(1) 表示时态

--- He has got married.

(2) 表示语态

--- He was sent to England.

(3) 构成疑问句：

--- Have you seen the doctor yet?

(4) 与否定副词not 合用，构成否定句：

-- I don’t like him.

(5) 加强语气：

--- Do come to the party tomorrow evening.

3. 常用的助动词的其他用法

(1) 以be 为中心词构成的半助动词be to ( 将要), be about to ( 即将要), be going

to (打算), be sure to ( 肯定), be likely to (很有可能）等，后接动词原形。

---- Autumn harvest is about to start.

---- They are sure to have a good ending.

(2) 以have 为中心词的半助动词have got to (必须), have to ( 不得不，必须), had

better ( 最好---)，后接动词原形

--- I ‘ve got to telephone him now.

--- We’ll have to stay here for the night.

(3) 以seem, appear, happen 等动词为中心的半助动词，后可接带to的动词不定

式，可以转化为it seems / appears / happens + that 结构

--- These grammar rules seem to be easy to me.

= It seems that these grammar rules are easy to me.

(二）情态动词：

1.情态动词的特殊用法：

(1) should

a. 表示义务或责任，意为“应该”，可用于各种人称

--- As a monitor, you should help him.

--- She shouldn’t waste any time in playing video games.

b. 用于第一人称时可以表示说话人的一种谦逊，客气, 委婉的语气

--- I should advise you not to do that.

c. 用在if引导的条件状语从句中，表示一件事听起来可能性很小，但也不是完

全没有可能，相当于“万一”

--- Ask her to ring me up if you should see her.

d. Why / How +should 结构表示说话人对某事不能理解感到意外，惊异等意

思，意为“竟会”

--- Why should you be so late today?

--- I don’t know why you should think that I did it.

注意：ought to 表义务，意为“应该”，语气比should 弱

( 2) would

a. 表示愿意，可用于各种人称

--- They would not let him in because he was poorly dressed.

--- I said I would do anything for you.

b. 表示委婉地提出请求建议或看法，可用于第二人称

--- Would you like another cup of coffee?

c. 表示过去反复发生的动作或过去的一种倾向

---Every time she was in trouble, she would go to him for help.

(3) dare 作情态动词和实义动词的用法区别

dare 的用法同need, 既可作情态动词，也可作实义动词。作实义动词时，在肯定句中，dare 后面通常接带to 的不定式，在否定和疑问句中，后面既可接带to 的不定式，也可接不带to 的不定式。

--- I wonder how he dared say that to the teacher.

( 情态动词）

--- We didn’t dare try a shot. ( 实义动词，否定句中省略to)

2. 情态动词后跟完成式和进行式的用法

(1) 情态动词后跟完成式，表“ 应当已经---”，“想必已经—”，“本来可以—”等意

义。不同的情态动词与动词完成形式连用表示不同的含义，通常有下列几种情况：

a. can’t / couldn’t have done sth. 表示推测过去不可能发生的事情

--- I didn’t see her in the meeting room this morning. She couldn’t have spoken at the meeting.

--- He can’t / couldn’t have attended the meeting yesterday.

b. must have done sth. 表示推测过去必然发生的事，语气较强，具有“肯定”的

意思。

--- I didn’t hear the phone. I must have been asleep.

注意：may ( might ) have done sth. 推测过去时间里可能发生的事情，用于肯定句和否定句

--- You may have read about it.

c. ought to / should have done sth. 表示本应该做某事而实际上没有做。其否定

式表示某种行为不该发生但却发生了。

--- I should have finished the work earlier.

--- You ought to have thrown the old clothes away.

d. “might / could +动词完成形式” 可表示婉转地责备某人过去应做某事而未

做，另外“might / could+ 动词完成形式”经常表示过去可能做了某事