The fire spread through the hotel very quickly but
everyone_____get out.
A.had to B.would C.couldD.was able to
表示“推断、判断”的can
may,must
在肯定句中都可以用来表示可能。在含义上must语气最肯定,may表示的是事实上的可能性。
shall not/shan’t do
Shall…do…?
Yes,…shall.
No,…shan’t.
should
应当，应该（表义务责任）
本该（含有责备意味）
should not/shouldn’t do
Should…do…?
will
意愿，决心
请求，建议，用在问句中would比较委婉
will not/won’t do
If I had been free,I would have visited you.
与将来事实相反
从句动词：过去式/should+动词原形/were+to do
主句动词：should/would/cou ld/might+动词原形
If it should rain tomorrow, we would not go camping.
A.will B.couldC.mayD.might
②Johnny, you_____play with the knife, you_____hurt yourself.
A.won’t/can’tB.mustn’t/may
C.shouldn’t/must D.can’t/shouldn ’t
在肯定句中could不可以用来表示过去某一特定场合的能力，而要用was/were able to。
在否定句中只能用can和may。所以can’t时用以代替mustn’t，语气比may更肯定。中文可以翻译为不可能。
Michael______be a policeman, for he’s much too short.
A.needn’tB.can’tC.should D.may
在疑问句只能用can，不能用may和must。
He may be very busy now. Can he be very busy now?
He must be very busy now. Can he be very busy now?
need
need作为情态动词只有一种形式，只用于否定句和疑问句。
dare
dare作为情态动词用时有两种形式：dare和dared两个词形，除了可以用于否定句和疑问句外，还可以用于条件从句或表示怀疑的句子中。
must+ have done：对过去发生的行为肯定的推测。
其否定式为：cannot have done。
You must have seen the film.
You cannot have seen the film.
needn’t+ have done：本来不必要做的而实际上又做了。
You needn’t have watered the flowers,for it is going to rain.
混合虚拟条件句
不同时间的虚拟：各遵守各的规则
①If he had listened to me, he would not be in trouble now.
②If he had told me yesterday,I should know w hat to do now.
③If I were you, I would have gone to her birthday party.
No,…might not.
must
必须，应该（表主观要求）
肯定，想必（肯定句中表推测）
must not/mustn’t do
Must…do…? to.
Yes,…must.
No,…needn’t/don’t have
have to
只好，不得不（客观的必须，有时态和人称的变化）
don’t have to do
虚拟与陈述的混合：各遵守各的规则
①He could have passed the exam,but he wasn’t careful enough.
②You should have come earlier.The bus left a moment ago.
含蓄虚拟
条件句
but for+名词表示虚拟条件
注意：didn’t need to(have to)do：
没有必要做而实际上也没有做
I didn’t need to clean the wi_ndows.My sister did it 2 hours ago.
should(ought to)+ have done：本来应该做而实际上又没有做。其否定形式表示某中行为不该发生却发生了。
Do…have to do…?
Yes,…do.
No,…don’t.
ought to
应当（表示义务责任，口语中多用should）
ought not to/oughtn’t to do
Ought…to do…?
Yes,…ought.
No,…oughtn’t.
shall
用于一三人称征求对方意见
用于二三人称表示许诺、命令、警告、威胁等
句 子或主句中的谓语动词的形式视具体情况而定。这是考查考生应变能力的最佳试题。
---But for your timely warning,we ______ into great trouble.
---You know we’re friends.
Can he have got the book?
might(may)+ have done：对过去发生的行为不太肯定的推测。
He may not have finished the work.
If we had taken the other road, we might have arrived earlier .
He shall be punished.威胁
should
劝告、建议、命令、应该做、道义上的责任。
You should(ought to) go to class right away.
I should(ought to) help him because he is in trouble.
will/would
’t.
could
couldn’t do
may
可以（问句中表示请求）
可能，或许（表推测）
祝愿（用于倒装句中）
may not do
May…do…?
Yes,…may.
No,…mustn’t/can’t.
might
might not do
Might…do…?
Yes,…might
You could have done better, but you didn’t try your best.
cannot+ have done：表示对现在或过去行为的否定推测。
He cannot have been to tha t town.
can+主语+ have done：表示对过去行为的怀疑或不肯定（用在疑问句中）。
请求、建议，would比will委婉客气。
Would you pass me the book?
表示意志、愿望和决心。
I will never do that again.
They asked us if we would do that again
would可表示过去反复发生的动作或某种倾向。
During the vacation he would visit me every week
Peter______come with us tonight, but he isn’t very sure yet.
A.mustB.mayC.can D.will
而can表示的是逻辑上的可能性：
Mary is in poor health. She can be ill at any times.
表示许可时用may/might ,can/could都可以，但在问句中用could…?或might…？ 以使口气委婉客气，其回答一定要用can或may，以使回答口气明确（must表示一定，必须，mustn’t表示禁止，不许可）。
①—Could I call you by your first name? —Yes, you______
The wound would not heal.（伤口老是不能愈合）
would表示估计或猜想。
It would be about ten when he left home.
What would she be doing there?
情态动词+have done的用法
could+have done：本可以做而实际上未能做。
情态动词和虚拟语气情态动词
发布人：邱玲珊
分类：语法专题发布时间：2020-09-15 10:34:22阅读(3)评论(0)
情态动词和虚拟语气 情态动词
I.情态动词基本用法
情态动词
用 法
否定式
疑问式
简答式
can
能力（体力，智力，技能）
允许或许可（口语中常用）
可能性（表猜测，用于否定句或疑问句中）
can not / cannot /can’t do
shall
用于第一人称：征求对方的意见。