情态动词can有两种形式,动词原形(现在时)为can,过去式为could。
can(could)的基本用法是:
1)表能够。如:
I can lift this stone. 我能举起这块石头。(表体能)
Can you use chopsticks? 你能用筷子吗?(表技能)
I can see him tonight. 我今晚能见到他。(表可能)
can表能够时与短语be able to同义,但后者可用于各种时态。
can表能够时可用于各种句式。如:
She can play a few simple tunes on the piano. 她能在钢琴上弹一些简单的调子。(肯定句)
Can you write with your left hand? 你能用左手写字吗?(疑问句)
I can not promise you anything. 我不能答应你任何事。(否定句)
表示将来的时候,用短语will be able to。如:
I shall be able to earn my own living soon. 我很快就能自立了。
He says he’ll be able to be home for Christmas. 他说他能回家过圣诞节。
could主要指过去。如:
I said that I could go. 我说我能去。
Could the boy read before he went to school? 这男孩上学前能识字吗?
was或were+able也可以表示过去能够。如:
I was able to help you yesterday. 我昨天能帮你的。
但could也常可指现在或将来。如:
You could phone her, I suppose. 我看你可以给她打电话。
The river could easily overflow, couldn’t it? 河水可能容易泛滥,不是吗?
如could与动词原形的完成式连用,则指过去未实现的动作。如:
She could have explained the mystery. 她本能够解释这个秘密的。(实际上未解释)
2)表可能。如:
The moon cannot always be at the full. 月不可能常圆。
If it’s raining tomorrow, the sports can take place indoors. 如果明天下雨,运动会就可能在室内举行。
can表可能时可指现在或将来。如:
You can perhaps obtain a dog from the Dogs’ Home. 你也许可以从养狗场弄到一条狗。(肯定句)
What can he mean? 他可能是什么意义呢?(疑问句)
We can’t use the indefinite article with this noun. 我们不可以在这个名词前用不定冠词。(否定句)
表可能时,could可指过去。如:
He said he couldn’t agree more. 他说他再同意不过了。
could亦可指现在或将来,表虚拟语气。如:
It could be my mother. 可能是我母亲。
He could arrive tomorrow. 他可能明天到。
could与完成式连用,则指过去未实现的动作。如:
It could have been seen from here if it had not been so dark. 如果天不那么黑,你可能从这儿望见它的。(实际上已望不见)
3)表允许。如:
You can borrow my bike tomorrow. 明天你可以借用我的自行车。
表这个意义时,can用于疑问句时表要求,用于否定句时表不许。如:
Can you lend me a hand? 你能帮我一把吗?
This sort of thing can’t go on! 这类事不能再继续了!
could指现在时,仅用于疑问句表更委婉的要求。如:
Could I interrupt a moment? 我可以插句话吗?
这种表允许的用法可用于主句是过去式的名词性从句中。这时的could就指过去,如:
Father said I could swim in the river. 爸爸说我可以在河里游泳。
4)表怀疑。如:
Can it be true? 那会是真的吗?
表这个意义时,can仅用于一般疑问句,并有感情色彩。
can用于一般式,表现在。如:
Can he really be ill? 你真的会病吗?
can用于进行式,表将来。如:
Can he be making the investigation all alone? 他会独立进行调查吗?
can用于完成式,表过去。如:
Can she have told a lie? 她会说谎吗?
can用于完成式或完成进行式时亦可表持续的动作。如:
Can she really have been at home all this time? 她真的会一直在家吗?
Can she have been waiting for us so long? 她会等我们这么久吗?
could指现在时亦可有这些用法,但暗含着更不确定的意义。如:
Could it be true?
Could she be telling lies?
Could he have said it?
Could he have been at home all this time?
Could she have been waiting for us so long?
5)can’t表不大可能。如:
It can’t be true. 那不大可能是真的。
can’t会有感情色彩。如:
He can’t be really ill. 他不大可能真的病了。(指现在)
She can’t be telling lies. 她不大可能说谎。(指现在)
He can’t have said it. 他不大可能说这种话。(指过去)
She can’t have been at home all this time. 她不大可能一直在家。(指过去)
She can’t have been waiting for us so long. 她不大可能等我们这么久。(指过去)
could亦可有这些用法,但语气委婉。如:
It couldn’t be true.
She couldn’t be telling lies.
He couldn’t have said it.
She couldn’t have been at home all this time.
She couldn’t have been waiting for us so long.
6)can和could用于特殊疑问句,有感情色彩,表惊讶、迷惑等。如:
What can(could) he mean? 他可能是什么意义呢?
What can(could) he be doing? 他可能在干什么呢?
What can(could) he have done? 他可能干什么了呢?
Where can(could) he have gone to? 他可能去哪里了呢?
7)can与could的比较:can与could表能够与可能时,can表真实,could表非真实。如:
He can speak English. 他能说英语。(表能够)
He could speak English if necessary. 他在必要时能说英语。
You can get the book from the library. 你可以从图书馆借到这本书。(表可能)
You could get the book from the library if necessary. 你在必要时可从图书馆借到这本书。
表允许和推测时,只是could语气较为委婉,含义较不确定。如:
Can I use your pen? 我可以借用你的笔吗?(表允许)
Could I use your pen? (较为委婉)
Can it be true? 那可能是真的吗?(表推测)
(69)Could it be true? (较不确定)
(70)It can’t be true. 那不大可能是真的。(表不大可能)
(71)It couldn’t be true. (较不确定)
8)用于固定习语。如:
She can’t help crying. 她不禁哭起来。
He couldn’t help laughing. 他不禁笑起来。
I can’t but ask him about it. 关于这件事我只得问他。
They couldn’t but refuse him. 他们不得不拒绝他。
whereismytoyplane.lcan.t/it怎样写
The girl couldn't help falling in love with a boy . In spite of her parents' opposition, she eloped with the boy . Her parents tried to contact her but she was determined to marry him . Undoutedly ,sometimes love can make people lose their mind .
...可不可以写成缩写“it's”?如果不可以请说明原因,在什么样的情况...
简单回答中,it is不能连写.否则句子重音就会无着落.如果it is后面跟着表语,形成完整回答,则统统可以缩略成it's.第二个问题是两种缩写都可以,只是it's not更强调否定意思.回答补充:it isn't和it's not都是有的,而且有时可以互换.上边说了,差别在于语气.一般来说,it isn't...后面可能会跟上it is.但it's not就不一定会带出这个尾巴.
什么样的句子中可以加haven't?
①: have got I have got to school in the morning.(我早上就到学校了) I have got the news .(我知道这个消息了) I have got the letter you wrote to me.(我收到你写给我的信了) All the students have got to the playground.(所有的学生都到操场了) You have got the answer.(你已经得到答案了)②:I haven't got any letter.(我没收到任何信) I haven't got any word that you said.(我还没听到你说什么) I haven't got any book yet.(我一本书也没拿到) I haven't got any money.(我没拿到一分钱) I haven't got any apple .(我一个苹果也没领到) ③:has got He has got to school(他到学校了) He has got the name of hers(他知道她的名字了) She has got the mark on the tree(她知道树上做的标记了) Everyone has got to the classroom。
(所有人都去了教室) She has got an apple.(她得到了个苹果)④:hasn't got She hasn't to the table to have supper.(她还未走到桌前来吃中午饭) He hasn't got the bike.(他还未领到车子) She hasn't got up .(她还没起床) He hasn't got downstairs.(他还未下楼呢) She hasn't got the correct right.(她还没有获得正确的待遇)...
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