情态动词
情态动词的语法特征
1） 二胡难学吗情态动词不能表示正在发生或已经发生的事情，只表示期待或估计某事的发生。
2） 情态动词除ought 和have 外，后面只能接不带to 的不定式。
3） 情态动词没有人称，数的变化，即情态动词第三人称单数不加-s。
4） 情态动词没有非谓语形式，即没有不定式，分词，等形式。情态动词没有人称和数的变化。
5胖大海功效）大多数情态动词有过去式。
难点：不同情态动词的辨析
解题方法：明确不同情态动词的不同之处，借助例句来理解，尤其注意句子语境
考点一、 基本用法的辨析：
1. may be & maybe
May be （可能是）--- maybe （或许）（副词）
The news may be true.
Maybe the news is true.
2.May not & can not
may not 译为“可能不”、“也许不会”而非“不可以”。“不可以”为must not或can‘t（不许，不可以）。
---May I smoke here?
---No, you mustn’t. /you can’t /you can not.
The news may not be true.
You mustn’t move any of the papers on the desk.
3.Can & be able to
Be able to 可以表示更多的时态。
can 可以表示许可。
We will be able to finish the work tomorrow.
4.ought to的否定式
ought to的否定式是ought not to，疑问句只把ought提前。
5.should 和ought to
两者可表示"想必一定，按理应该"的意思。
6.Must
Must do
Must be
Must have done
Must 的反意疑问句
I must get up at six, ___？
She must be in the classroom now, _____?
They must have had great trouble trying to get there, ____?
用 must 提问时的回答
肯定回答：must
否定回答：needn’t或don’t /doesn’t have to
Must I come as early as 6 tomorrow morning?
Yes, you must.
No, you needn’t. / No, you don’t have to.
7.Mustn’t & Needn’t
Must he arrive very early?
No, he doesn’t have to / No, he needn’t.
8.Must & have to
Must: 主观上认为“必须” 作某事。
Have to: 受客观情况迫使而“不得不” 婚礼风格作某事
Must & have to时态的区别
Must只用于现在 , 而have to则可用于不同时态。用had to表示过去, 用will have to表示将来。
We had to resort to force in that ca.
We will have to reconsider the whole thing if this plan fails.
One must have faith in life.
9.Need & dare
Need & dare 既能作实义动词，又能作情态动词。
Need & dare在肯定句中，通常为实义动词，后面的不定式要带从来没有to，单数第三人称加s，有时态变化。
涉密会议
Need & dare作情态动词时，多用于否定句和疑问句。
eg. She needs to work even harder if she wants to succeed in her study.
He dares to speak the truth.
Do you need to take a break?
They didn’t dare to disobey.
Need he leave so soon?
You needn’t have done all the heavy work.
She dare not go home late at night.
How dare you say I am unfair?
10.might as well
might as well译为“不妨”表示规劝。
You might as well wait to e what I can do for you.
11.be to 可视为情态动词
be to的三种意义
①系表结构
My duty is to instruct students on what is wrong and what is right.
②将来时的特殊表达法
I was to go back home when the phone called.
③“应当”“规定是”可视为情态动词 –be suppod to
You are to obey the school rules and regulations.
阿胶糕的功效与作用12.Would rather
表意愿：I would rather/sooner not go there on my own.
表选择：She would rather die than surrender to the enemy.
（句型Would rather do sth. than do sth. el）
表虚拟：would rather sb. did /didn’t do sth.什么是母乳性黄疸
I would rather you didn’t do anything for the time being.
would rather表示"宁愿"
would rather do
would rather not do
would rather… than… 宁愿…而不愿。
还有would sooner, had rather, had sooner都表示"宁愿"、"宁可"的意思。例如：
If I have a choice, I had sooner not continue my studies at this school.
I would rather stay here than go home. = I would stay here rather than go home.
13.Ud to & would
情态动词ud to表“过去常常做”得图。往往含有“不再如此”之意。
Would只能表示动作，不能表示状态。而ud to都可以。 .
He would ask the teacher some strange questions.
He ud to ask the teacher ……
He ud to be much better off than he is now.
He would be much …… (wrong)
考点二、情态动词表推测
解题方法：明确不同情态动词的语气不同之处，借助例句来理解，尤其注意句子语义和时间状语
can, could, may, might, must 皆可表示推测，其用法如下：
1. 情态动词+动词原形，表示对现在或将来的情况的推测，此时动词通常为系动词。例如：
I don't know where she is, she may be in Wuhan.
2. 情态动词+动词现在进行时，表示对现在或将来正在进行的情况进行推测。例如：
At this moment, our teacher must be correcting our exam papers.
3. 情态动词+动词完成时，表示对过去情况的推测。例如：
The road is wet. It must have rained last night.
4. 情态动词+动词的现在完成进行时，表示对过去正在发生事情的推测。例如：
Your mother must have been looking for you.
5. 推测的否定形式，疑问形式用can't, couldn't表示。例如：
Mike can't have found his car, for he came to work by bus this morning.
注意：could, might表示推测时不表示时态，其推测的程度不如can, may。
6. 对现在或客观事实的推测对现在或客观事实的肯定推测一般用must, will, should, may(might)或could，语气依次递减。
例：Helen _____go on the trip with us but she isn’t quite sure yet.
A. shall B. must C. may D. can
例：—I’ve taken someone el’s green sweater by mistake.
—It ___ Harry’s. He always wears green.
A. has to be B. will be C. mustn’t be D. could be
例：That, I think, ____ be all that I want to say.
A. can B. could C. will D. ought to
C、D、C。
7. 对现在或客观事实的否定推测，常用cannot译为“根本不可能”、“想必不会”，表示推测的语气非常肯定, may not, might not或could not译为“可能不”、“也许不”，表示推测的语气不很肯定。
例：You might just as well tell the manufacturer that male customers ______ not like the design of the furniture.
A. must B. shall C. may D. need
例：--Isn’t that Ann’s husband over there?
--No, it _______ be him ---I’m sure he doesn’t wear glass.
A. can’t B. must not C. won’t D. may not
C、 A。
