如:There was plenty of time. She needn't have hurried .
4、“can’t /couldn’t+have done /been-------”表示“过去不可能发生了某事或存在过某种状态”。
如:
I saw him just now. He can’t have gone to Japan.
She said the man couldn’t have stolen her car.
5、“could+have done/been-------”表示“过去本来能够,可以做某事或成为某种状态,而实际上没有”,说话者有些遗憾。“could sb. have done /been-------?”是它的问句形式。如:You could have stayed with the Smiths while you were in New York (but in fact you stayed in a nearby hotel .) Could Mr Li have helped this girl student?
6、“may/might+完成式”表示“过去可能,本来可以于某事而实际上没有干”,might的可能性较小,语气较弱。如:He may have finished reading the book. She might have given you some help,however bus she was.
【情态动词易混点归纳】
易混点一: can和be able to:
两者表示能力时用法相同,但can只有原形“can”和过去式“could”两种形式,在其他时态中要用be able to来表示。另外be able to常常指经过努力,花费了时间和劳力之后才能做到某事。
如:Jim can’t speak English.吉姆不会说英语。
He could speak English at 5.他五岁时就会说英语。
We’ll be able to see him next week.下星期我们将会见到他。
He has been able to drive.他已经会开车了。
I’m sure you’ll be able to finish it quickly.我相信你能迅速地完成。
We were able to reach the top of the mountain at noon.我们能在中午到达山顶。
易混点二:can和may
1. can和may均可用来征求意见或许可,意为“可以”,一般可互换使用。如:Can/ May I help you ? 我能帮助你吗?
2. can和may表示可能性时的区别:
1)在肯定句中用might,may,must,不用can
2)在疑问句中表示推测用can,不用might,may,must
3)在否定句中用can’t(不可能),不用may,must。
如:She may be in the classroom .她可能在教室里。
Where can they be now?他们现在可能在哪儿?
That can’t be true.那不可能是真的。
易混点三: may be和maybe
用法区别 常用位置
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