情态动词的用法,求总结

yinyin2007 1年前 已收到1个回答 举报

帅小妞 幼苗

共回答了24个问题采纳率:87.5% 举报

情态动词有can (could), may (might), must, have to, shall (should, will (would), dare (dared), need (needed), ought to等。 情态动词无人称和数的变化;不能单独使用,必须与其后的动词原形构成谓语。
一、 can, could
1) 表示能力(体力、知识、技能)。
Can you lift this heavy box?(体力)
Mary can speak three languages.(知识)
Can you skate?(技能)
此时可用be able to代替。Can只有一般现在时和一般过去式;而be able to则有更多的时态。
I’ll not be able to come this afternoon.
当表示“经过努力才得以做成功某事”时应用be able to,不能用Can。如:
He was able to go to the party yesterday evening in spite of the heavy rain.
2) 表示请求和允许。
-----Can I go now?
----- Yes, you can. / No, you can’t.
此时可与may互换。在疑问句中还可用could,might代替,不是过去式,只是语气更委婉,不能用于肯定句和答语中。
---- Could I come to see you tomorrow?
---- Yes, you can. ( No, I’m afraid not. )
3) 表示客观可能性(客观原因形成的能力)。
They’ve changed the timetable, so we can go by bus instead.
This hall can hold 500 people at least.
4) 表示推测(惊讶、怀疑、不相信的态度),用于疑问句、否定句和感叹句中。
Can this be true?
This can’t be done by him.
How can this be true?
二、 may, might
1) 表示请求和允许。might比 may语气更委婉,而不是过去式。否定回答时可用can’t或mustn’t,表示“不可以,禁止”。
----Might/ May I smoke in this room?
---- No, you mustn’t.
---- May/Might I take this book out of the room?
---- Yes, you can. (No, you can’t / mustn’t. )
用May I...?征徇对方许可时比较正式和客气,而用Can I...?在口语中更常见。
2)用于祈使句,表示祝愿。
May you succeed!
3) 表示推测、可能性(不用于疑问句)。
might不是过去式,它所表示的可能性比may小。
1.He may /might be very busy now.
2.Your mother may /might not know the truth.
三、 must, have to
1) 表示必须、必要。
You must come in time.
在回答引出的问句时,如果是否定的,不能用mustn’t(禁止,不准),而用needn’t, don’t have to(不必).
---- Must we hand in our exercise books today?
---- Yes, you must.
---- No, you don’t have to / you needn’t.
2) must是说话人的主观看法, 而have to则强调客观需要。Must只有一般现在时, have to 有更多的时态形式。
1. he play isn’t interesting, I really must go now.

1年前 追问

1

举报 帅小妞

3) 表示推测
should , ought to (客观推测), must(主观推测)。
1.He must be home by now. (断定他已到家)
2.He ought to/should be home by now.(不太肯定)
3. This is where the oil must be.(直爽)
4. This is where the oil ought to/should be.(含蓄)
八、 情态动词+不定式完成式(have done)
1) can / could + have done在肯定句中表示“本来可以做而实际上能做某事”,是虚拟语气;在疑问句或否定句中表示对过去行为的怀疑或不肯定, 表示推测。
1. You could have done better, but you didn’t try your best. (虚拟语气)
2. He can’t have been to that town.(推测)
3. Can he have got the book?(推测)
2) may / might +不定式完成式(have done)
表示对过去行为的推测。不能用于疑问句中,没有虚拟语气的用法。Might所表示的可能性比may小。
1. He may not have finished the work .
2. If we had taken the other road, we might have arrived earlier.
3)must +不定式完成式(have done)
用于肯定句中,表示对过去行为的推测。意为“一定、想必”。其疑问、否定形式用can,can’t代替。参看1) can / could + have done表示推测。
1. You must have seen the film Titanic.
2. He must have been to Shanghai.
4)should +不定式完成式(have done)
用于肯定句中,表示对过去行为的推测。
He should have finished the work by now。
表示“本应该做而实际上没有做某事”,其否定式表示某种行为本不该发生却发生了。可以与ought to +不定式完成式(have done)互换。
1. You ought to / should have helped him. (but you didn’t.)
2. She shouldn’t have taken away my measuring tape, for I wanted to use it.
5) needn’t +不定式完成式(have done)
表示“本来不必做而实际上做了某事”。
You needn’t have watered the flowers, for it is going to rain.
6) will +不定式完成式(have done)
主要用于第二、三人称,表示对已完成的动作或事态的推测。
He will have arrived by now.

举报 帅小妞

希望对你有帮助,祝你学习更上一层楼!望采纳,谢谢。
可能相似的问题
Copyright © 2024 YULUCN.COM - 雨露学习互助 - 18 q. 0.290 s. - webmaster@yulucn.com