【情态动词】
特征
1. 情态动词+do
2. 情态动词本身没有时态，人称数的变化，如想体现时态需从其后所加结构入手： . do/be 现在，将来
be doing正在进行
have done 过去
3. 用法：
一．can/could
①用于疑问句中表请求，could 比can 委婉，可用于各个人称，
回答时表允许用can 不用could
—Could you do me a favor?
—Yes, I can
②表能力，could 是can 的过去式，表自身具有的简单能力
can 与be able to的区别：后者是指经过一番努力或在特定情况中获得的能力 My leg hurts, but I am able to swim quickly.
I can swim
The light was dim, but he was able to see it.
The fire spread very fast, but they were able to escape.
③can ’t/couldn’t …比较级/too/enough
再…不过分；越…越好
You can’t be too careful
=You can’t be careful enough.
You couldn’t have chosen a better gift for me.
4.can ’t/couldn’t do/be 不可能要做，不可能是，对现在或将来事实的否定推测 be doing 不可能正在做，对正在进行事实的否定推测，
have done 不可能做过了，对过去事实的否定推测
It can’t have rained last night.
Tom can’t be sleeping now.
Tom can’t go abroad tomorrow, because he is ill.
can, could也用于疑问句中表推测
where can he have gone on such a rainy night?
5.can (1)用于否定句，疑问句，感叹句中表惊讶，怀疑，不相信的态度
How can it be sure?
(2)can表客观的，理论的可能性，有时候可能会，有时候也会
常与at times, sometimes等词连用；具体事实的可能性用may/might; Accidents can happen on such a rainy day.(理论)
The weather is hot in May, but it can be cool sometimes.(客观)
Mary may come tonight, but she isn’t sure.(具体的一件事)
6.could,could have done表过去本来有能力做某事，但实际上没做，带有遗憾语气 They could have passed the exam but they were too careless.
7. can’t/couldn’t help doing情不自禁
can ’t/couldn’t help (to) do 不能帮助做某事
can ’t (help) but do sth. 不得不做某事，只好做
There is no help for it=It can’t be helped=I can’t help it.(我也无能为力。)
二．may/might
1. 用于疑问句中表请求，只用于第一人称，might 比may 语气委婉，
回答时表允许用may ，不用might.
肯定：may
否定：mustn ’t, had better not ,can’t
2. may/might(just) as well do sth.还是做…的好，不妨…的好
Since you want to catch the first bus, you may as well go now.
3. may well do sth.=be very likely to do sth.很可能
might well do=be likely to do 多半会，有可能
Mary ___ well not want to go travelling, because she hates travelling.
A can B may C need D must ★去掉well 后选A 4.may/might do/be 可能要做，可能是，对现在和将来事实的可能性推测
be doing 可能正在做，对正在进行事实的可能性推测
have done 可能做过了，对过去事实的可能性推测
[注]以上句子可用于肯定句，否定句中，疑问句中只用might 不用may
5. 表祝愿:May you succeed!
May you be happy.
. 三．must/have to
1.must 主观必须做 have to 客观不得不
2.must 提出问句，肯定回答：must; 否定回答：needn ’t, don’t have to
3.must do/be: 一定要做，一定是；对现在，将来事实的肯定推测， be doing一定正在做；:对正在进行事实的肯定推测，
have done一定做过了；:对过去事实的肯定推测，
★★★肯定事实的推测用must ，否定事实推测用can ’t/couldn’t ，肯定可能性推测
用may/might，否定可能性推测用may not/might not ，疑问句中表推测用can/could/might
情态动词表推测时，反意疑问句中的助动词取决于情态动词后的助动词；如有明显的过去时间，引用did(动作) ，was, were（状态或被动）
You must be from Japan, aren’t you?
It must have rained last night, didn’t it?
It can’t have rained, has it?
Tom must be sleeping when I get home, wasn’t he?
Tom may have been told the news when I got home, wasn’t he?
5.mustn ’t 表示严令禁止，一定不能，反意疑问用must
Children mustn’t play with fire, must they?
6.must 表必须时，反意疑问用need.
We must obey the rule, needn’t we?
7. 偏偏，硬要表示不耐烦，不情愿的语气
It ’s midnight, must you play the piano so late?
Could I use your car?---Well…If you must..
四.need/dare 实义动词+to do
情态动词+do
I dare not go out at night.
I don’t dare to go out at night.
He needn’t buy this book.
He doesn’t need to buy this book.
1..need 提出问句，肯定回答用must 和have to ,否定用needn ’t
2. need have done 本来有必要做但没做
needn ’t have done 本来没有必要做的事但做了 （抱怨）
didn ’t need to do=didn’t have to do=it wasn’t necessary to do sth
. 过去没必要做实际也没做了
五.shall
1. 用于第一，三人称疑问词时表示请求或向对方征求意见，希望得到回答 What shall we do next step?
Shall he come in?
2. 主语站在自己的角度去说别人的事情，进而表达命令，警告，许诺，威胁 Watch out for ink. You shall not get rid of it.(警告)
My mother told me if I passed the exam I shall go to Beijing..(许诺)
You shall die sooner or later.(威胁)
3. 宣布法律，条文规范等
Children under 18 shall not surf the Internet in our country.
It ’s our hotel rule “All the payments shall be made in cash”.
should
1. 表示劝告，建议，命令，义务=ought to应该(疑问句中用should 代替ought to ) You should protect the environment.
You should take your teacher’s advice.
You should obey the rule.
2. 竟然，表惊讶，遗憾的情绪
It ’s strange that he should have done such a stupid thing.
You should were slippers at work..
3. 对某种情况的推测表示按常理常规或一般情况下的推测，
说话者有较大的试探性
⑴I should arrive home in ten minutes.
⑵ When can I take it back?--- It be on Friday.
A must B should C may D can
⑶Since you have made so much preparation,
you shouldn’t have any problem in passing the exam.
4.should be doing应该正在做某事，语气介于must be doing和
may/might be doing之间
5.should have done=ought to have done 过去本应该做但没有做
shouldn ’t have done=oughtn’t to have done 过去不该做但做了(受之有愧之意 ) Thank you very much, you shouldn’t have bought a gift for me.
六.will 和would
1.will 和would 用于疑问句中和第二人称连用表请求Will you pass me the book?
2.will would
(1)表现在将来的意志愿望和决心 (1)表过去的意志，愿望和决心
(2)表现在经常性习惯性倾向性动作(2)would do过去常常做某事现在有可能还做
used to do过去常常做，现在不做了
I won’t do that again. Whatever I said to my mother, she wouldn’t pay attention to me. He will sat here, reading for hours. Each time he came, he would bring me flowers.
3.will 表示作用或功能(would=could)
I can swim.
The room will/can /would/could hold 100 people.
The door won’t open.
4.will 表示不肯定推测：可能，比should 的语气弱，比may, might的语气强 That man at the door will be postman.
5.would 用在过去否定句中表示拒绝此行为或无此习惯，
用于something 时表示拟人化 “不肯，不愿意”
The door wouldn’t open.(这个门怎么也不肯开)
The door won’t open. (这个门打不开了，强调不好使)
七had better 最好
had better do
had better not do;
had better have done(最好已经做过了某事---虚拟)
八 would rather 宁愿，宁可
would rather do
would rather not do
would rather sb did(现在或将来的事)
had done(过去式的事)
【总结】
肯定事实的推测用must ，否定事实推测用can ’t/couldn’t ，肯定可能性推测用may/might，否定可能性推测用may not/might not, 疑问句中表推测用can/could/might
肯定句：must>should>will>may>might
否定句：can ’t>couldn’t>shouldn’t>won’t>may not>might not
Should 表对某种情况的推测表示按常理常规或一般情况下的推测，
说话者有较大的试探性
⑴I should arrive home in ten minutes.
⑵ When can I take it back?--- It should be on Friday.
Will 表示不肯定推测：可能，比should 的语气弱，比may, might的语气强 That man at the door will be postman.
【虚拟语气】
主将从现 If it doesn’t rain, I will go swimming.
真实语气主现从现 Do you mind if I open the door?
If 条件状语从句
---假设---时态----往过去推
If I had taken my teacher’s advice, I would have passed the exam
If I became/were to become/should become a millionaire, I could buy….
1. 如果主句从句表达的时间不一致，主从句的时态根据自己的时间做出调整 (错综虚拟语气)
If you had studied hard then, you could go to college now
2含蓄虚拟条件句：有时if 从句可用介词短语替代：but for ，otherwise(否则) ，without 如果不是，没有
If it hadn’t been for his help, I wouldn’t have solved the problem.
Without/ but for his help, I wouldn’t have solved the problem.
2. if 条件状语从句中使用虚拟时，可省略if ，助动词were had should 提于句首 （not 不可提前）
Were I a bird, I couldn’t study.
Were it to rain/Should it rain tomorrow, I would put off the match.
4. 真实语气与虚拟语气相结合
1. 通过虚拟语气的结构，确定事情发生的时间，进而选择真实语气的时态。 ○
If the weather had been better, we could have had a picnic.
2. 通过真实语气的时态，确定事情发生的时间，进而选择虚拟语气的时态。 ○
二．
if only 但愿„该多好+感叹句 现：did/were
wish 希望+宾从 过：had done
as if/though 似乎好像+表从/状从 将：could/would+do
I wish I were a bird.=If only I were a bird.
I wish I had taken your advice.=If only I had taken your advice.
I wish I could become a teacher.=If only I could become a teacher.
It looks as if he were angry
It looked as if he had been angry
三．
It is (high/about) time that sb did sth
sb should(不可省) do sth
It ’s time for sb(宾) to do sth (可以做)
四．would rather sb did sth(现，将)
had done sth (过去)
would rather do;
would rather not do ;
would rather do A than do B
=would do A rather than do B
=prefer doing A to doing B
=prefer to do A rather than do B
=prefer to do A instead of doing B
五．should+do：
1. 表建议，请求，命令的词与名词性从句连用时，名词从句中用sb should do （should 可省）的虚拟语气结构
建议：suggest ，propose ， advice ， recommend
要求：urge ，require ，request ，demand ，insist
命令：order ，command
suggest —表暗示，表明不用虚拟；建议用虚拟语气
insist —坚持说，坚持认为不用虚拟；坚持要求用虚拟语气
2It is ①a pity/a shame that sb. should do sth
②strange/surprise
③necessary/important/essential/natural.
★ 考点一 it 充当形式主语，that 引导真正的主语从句
★ 考点二 主语从句中用sb. should do sth的虚拟语气结构
★ 考点三Should 在①②中译为竟然，在③中译为应该
★ 考点四整个结构表惊讶，惋惜，理应如此等情绪：
It ’s a pity that you should miss the match.
It ’s strange that you should wear slippers at work.
It ’s essential that we should protect the environment
3 in case （that ）
lest sb should do sth
for fear （that ）
【情态动词】
特征
1. 情态动词+do
2. 情态动词本身没有时态，人称数的变化，如想体现时态需从其后所加结构入手： . do/be 现在，将来
be doing正在进行
have done 过去
3. 用法：
一．can/could
①用于疑问句中表请求，could 比can 委婉，可用于各个人称，
回答时表允许用can 不用could
—Could you do me a favor?
—Yes, I can
②表能力，could 是can 的过去式，表自身具有的简单能力
can 与be able to的区别：后者是指经过一番努力或在特定情况中获得的能力 My leg hurts, but I am able to swim quickly.
I can swim
The light was dim, but he was able to see it.
The fire spread very fast, but they were able to escape.
③can ’t/couldn’t …比较级/too/enough
再…不过分；越…越好
You can’t be too careful
=You can’t be careful enough.
You couldn’t have chosen a better gift for me.
4.can ’t/couldn’t do/be 不可能要做，不可能是，对现在或将来事实的否定推测 be doing 不可能正在做，对正在进行事实的否定推测，
have done 不可能做过了，对过去事实的否定推测
It can’t have rained last night.
Tom can’t be sleeping now.
Tom can’t go abroad tomorrow, because he is ill.
can, could也用于疑问句中表推测
where can he have gone on such a rainy night?
5.can (1)用于否定句，疑问句，感叹句中表惊讶，怀疑，不相信的态度
How can it be sure?
(2)can表客观的，理论的可能性，有时候可能会，有时候也会
常与at times, sometimes等词连用；具体事实的可能性用may/might; Accidents can happen on such a rainy day.(理论)
The weather is hot in May, but it can be cool sometimes.(客观)
Mary may come tonight, but she isn’t sure.(具体的一件事)
6.could,could have done表过去本来有能力做某事，但实际上没做，带有遗憾语气 They could have passed the exam but they were too careless.
7. can’t/couldn’t help doing情不自禁
can ’t/couldn’t help (to) do 不能帮助做某事
can ’t (help) but do sth. 不得不做某事，只好做
There is no help for it=It can’t be helped=I can’t help it.(我也无能为力。)
二．may/might
1. 用于疑问句中表请求，只用于第一人称，might 比may 语气委婉，
回答时表允许用may ，不用might.
肯定：may
否定：mustn ’t, had better not ,can’t
2. may/might(just) as well do sth.还是做…的好，不妨…的好
Since you want to catch the first bus, you may as well go now.
3. may well do sth.=be very likely to do sth.很可能
might well do=be likely to do 多半会，有可能
Mary ___ well not want to go travelling, because she hates travelling.
A can B may C need D must ★去掉well 后选A 4.may/might do/be 可能要做，可能是，对现在和将来事实的可能性推测
be doing 可能正在做，对正在进行事实的可能性推测
have done 可能做过了，对过去事实的可能性推测
[注]以上句子可用于肯定句，否定句中，疑问句中只用might 不用may
5. 表祝愿:May you succeed!
May you be happy.
. 三．must/have to
1.must 主观必须做 have to 客观不得不
2.must 提出问句，肯定回答：must; 否定回答：needn ’t, don’t have to
3.must do/be: 一定要做，一定是；对现在，将来事实的肯定推测， be doing一定正在做；:对正在进行事实的肯定推测，
have done一定做过了；:对过去事实的肯定推测，
★★★肯定事实的推测用must ，否定事实推测用can ’t/couldn’t ，肯定可能性推测
用may/might，否定可能性推测用may not/might not ，疑问句中表推测用can/could/might
情态动词表推测时，反意疑问句中的助动词取决于情态动词后的助动词；如有明显的过去时间，引用did(动作) ，was, were（状态或被动）
You must be from Japan, aren’t you?
It must have rained last night, didn’t it?
It can’t have rained, has it?
Tom must be sleeping when I get home, wasn’t he?
Tom may have been told the news when I got home, wasn’t he?
5.mustn ’t 表示严令禁止，一定不能，反意疑问用must
Children mustn’t play with fire, must they?
6.must 表必须时，反意疑问用need.
We must obey the rule, needn’t we?
7. 偏偏，硬要表示不耐烦，不情愿的语气
It ’s midnight, must you play the piano so late?
Could I use your car?---Well…If you must..
四.need/dare 实义动词+to do
情态动词+do
I dare not go out at night.
I don’t dare to go out at night.
He needn’t buy this book.
He doesn’t need to buy this book.
1..need 提出问句，肯定回答用must 和have to ,否定用needn ’t
2. need have done 本来有必要做但没做
needn ’t have done 本来没有必要做的事但做了 （抱怨）
didn ’t need to do=didn’t have to do=it wasn’t necessary to do sth
. 过去没必要做实际也没做了
五.shall
1. 用于第一，三人称疑问词时表示请求或向对方征求意见，希望得到回答 What shall we do next step?
Shall he come in?
2. 主语站在自己的角度去说别人的事情，进而表达命令，警告，许诺，威胁 Watch out for ink. You shall not get rid of it.(警告)
My mother told me if I passed the exam I shall go to Beijing..(许诺)
You shall die sooner or later.(威胁)
3. 宣布法律，条文规范等
Children under 18 shall not surf the Internet in our country.
It ’s our hotel rule “All the payments shall be made in cash”.
should
1. 表示劝告，建议，命令，义务=ought to应该(疑问句中用should 代替ought to ) You should protect the environment.
You should take your teacher’s advice.
You should obey the rule.
2. 竟然，表惊讶，遗憾的情绪
It ’s strange that he should have done such a stupid thing.
You should were slippers at work..
3. 对某种情况的推测表示按常理常规或一般情况下的推测，
说话者有较大的试探性
⑴I should arrive home in ten minutes.
⑵ When can I take it back?--- It be on Friday.
A must B should C may D can
⑶Since you have made so much preparation,
you shouldn’t have any problem in passing the exam.
4.should be doing应该正在做某事，语气介于must be doing和
may/might be doing之间
5.should have done=ought to have done 过去本应该做但没有做
shouldn ’t have done=oughtn’t to have done 过去不该做但做了(受之有愧之意 ) Thank you very much, you shouldn’t have bought a gift for me.
六.will 和would
1.will 和would 用于疑问句中和第二人称连用表请求Will you pass me the book?
2.will would
(1)表现在将来的意志愿望和决心 (1)表过去的意志，愿望和决心
(2)表现在经常性习惯性倾向性动作(2)would do过去常常做某事现在有可能还做
used to do过去常常做，现在不做了
I won’t do that again. Whatever I said to my mother, she wouldn’t pay attention to me. He will sat here, reading for hours. Each time he came, he would bring me flowers.
3.will 表示作用或功能(would=could)
I can swim.
The room will/can /would/could hold 100 people.
The door won’t open.
4.will 表示不肯定推测：可能，比should 的语气弱，比may, might的语气强 That man at the door will be postman.
5.would 用在过去否定句中表示拒绝此行为或无此习惯，
用于something 时表示拟人化 “不肯，不愿意”
The door wouldn’t open.(这个门怎么也不肯开)
The door won’t open. (这个门打不开了，强调不好使)
七had better 最好
had better do
had better not do;
had better have done(最好已经做过了某事---虚拟)
八 would rather 宁愿，宁可
would rather do
would rather not do
would rather sb did(现在或将来的事)
had done(过去式的事)
【总结】
肯定事实的推测用must ，否定事实推测用can ’t/couldn’t ，肯定可能性推测用may/might，否定可能性推测用may not/might not, 疑问句中表推测用can/could/might
肯定句：must>should>will>may>might
否定句：can ’t>couldn’t>shouldn’t>won’t>may not>might not
Should 表对某种情况的推测表示按常理常规或一般情况下的推测，
说话者有较大的试探性
⑴I should arrive home in ten minutes.
⑵ When can I take it back?--- It should be on Friday.
Will 表示不肯定推测：可能，比should 的语气弱，比may, might的语气强 That man at the door will be postman.
【虚拟语气】
主将从现 If it doesn’t rain, I will go swimming.
真实语气主现从现 Do you mind if I open the door?
If 条件状语从句
---假设---时态----往过去推
If I had taken my teacher’s advice, I would have passed the exam
If I became/were to become/should become a millionaire, I could buy….
1. 如果主句从句表达的时间不一致，主从句的时态根据自己的时间做出调整 (错综虚拟语气)
If you had studied hard then, you could go to college now
2含蓄虚拟条件句：有时if 从句可用介词短语替代：but for ，otherwise(否则) ，without 如果不是，没有
If it hadn’t been for his help, I wouldn’t have solved the problem.
Without/ but for his help, I wouldn’t have solved the problem.
2. if 条件状语从句中使用虚拟时，可省略if ，助动词were had should 提于句首 （not 不可提前）
Were I a bird, I couldn’t study.
Were it to rain/Should it rain tomorrow, I would put off the match.
4. 真实语气与虚拟语气相结合
1. 通过虚拟语气的结构，确定事情发生的时间，进而选择真实语气的时态。 ○
If the weather had been better, we could have had a picnic.
2. 通过真实语气的时态，确定事情发生的时间，进而选择虚拟语气的时态。 ○
二．
if only 但愿„该多好+感叹句 现：did/were
wish 希望+宾从 过：had done
as if/though 似乎好像+表从/状从 将：could/would+do
I wish I were a bird.=If only I were a bird.
I wish I had taken your advice.=If only I had taken your advice.
I wish I could become a teacher.=If only I could become a teacher.
It looks as if he were angry
It looked as if he had been angry
三．
It is (high/about) time that sb did sth
sb should(不可省) do sth
It ’s time for sb(宾) to do sth (可以做)
四．would rather sb did sth(现，将)
had done sth (过去)
would rather do;
would rather not do ;
would rather do A than do B
=would do A rather than do B
=prefer doing A to doing B
=prefer to do A rather than do B
=prefer to do A instead of doing B
五．should+do：
1. 表建议，请求，命令的词与名词性从句连用时，名词从句中用sb should do （should 可省）的虚拟语气结构
建议：suggest ，propose ， advice ， recommend
要求：urge ，require ，request ，demand ，insist
命令：order ，command
suggest —表暗示，表明不用虚拟；建议用虚拟语气
insist —坚持说，坚持认为不用虚拟；坚持要求用虚拟语气
2It is ①a pity/a shame that sb. should do sth
②strange/surprise
③necessary/important/essential/natural.
★ 考点一 it 充当形式主语，that 引导真正的主语从句
★ 考点二 主语从句中用sb. should do sth的虚拟语气结构
★ 考点三Should 在①②中译为竟然，在③中译为应该
★ 考点四整个结构表惊讶，惋惜，理应如此等情绪：
It ’s a pity that you should miss the match.
It ’s strange that you should wear slippers at work.
It ’s essential that we should protect the environment
3 in case （that ）
lest sb should do sth
for fear （that ）