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
