Level: beginner
Possibility and impossibility
We use could to show that something is possible, but not certain:
They could come by car. (= Maybe they will come by car.)
They could be at home. (= Maybe they are at home.)
We use can to make general statements about what is possible:
It can be very cold here in winter. (= It is sometimes very cold here in winter.)
You can easily get lost in this town. (= People often get lost in this town.)
We use can't or cannot to say that something is impossible:
That can't be true.
You cannot be serious.
Level: intermediate
We use could have to make guesses about the past:
It's ten o'clock. They could have arrived by now.
Where are they? They could have got lost.
We use could to make general statements about the past:
It could be very cold there in winter. (= It was sometimes very cold there in winter.)
You could easily get lost in that town. (= People often got lost in that town.)
We use can't have or couldn't have to say that a past event was impossible:
They know the way here. They can't have got lost!
If Jones was at work until six, he couldn't have done the murder.
Ability
Level: beginner
We use can and can't to talk about someone's skill or general abilities:
She can speak several languages.
He can swim like a fish.
They can't dance very well.
We use can and can't to talk about the ability to do something at a specific time in the present or future:
I can see you.
Help! I can't breathe.
We use could and couldn't to talk about the past:
She could speak several languages.
They couldn't dance very well.
Level: intermediate
We use could have to say that someone had the ability or opportunity to do something, but did not do it:
She could have learned Swahili, but she didn't want to.
I could have danced all night. [but I didn't]
Permission
Level: beginner
We use can to ask for permission to do something:
Can I ask a question, please?
Can we go home now?
could is more formal and polite than can:
Could I ask a question please?
Could we go home now?
We use can to give permission:
You can go home now.
You can borrow my pen if you like.
We use can to say that someone has permission to do something:
We can go out whenever we want.
Students can travel for free.
We use can't to refuse permission or say that someone does not have permission:
You can't go home yet.
Students can't travel for free.
Requests
We use could you … as a polite way of telling or asking someone to do something:
Could you take a message, please?
Could I have my bill, please?
can is less polite:
Can you take a message, please?
Offers
We use can I … to make offers:
Can I help you?
Can I do that for you?
We sometimes say I can ... or I could ... to make an offer:
I can do that for you if you like.
I could give you a lift to the station.
Suggestions
We use could to make suggestions:
We could meet at the weekend.
You could eat out tonight.
Questions and negatives
We make questions by putting the subject after can/could:
| Can I ...? Could I ...? etc. |
Can you ...? Could you ...? |
The negative form is can't in spoken English and cannot in written English.
We sometimes say cannot, but it is very emphatic.
The negative form of could is couldn't in spoken English and could not in written English.
- can and could: possibility 1
- can and could: possibility 2
- can and could: other uses 1
- can and could: other uses 2
Comments
I am in the meeting now.
I am at the meeting now.
What do the two sentences actually mean? Which one of them should we use when talking about the fact that we are involved in it?
Hello Girikumar
I'd probably say 'in' here, but I think both 'in' and 'at' are fine. As far as I know, there's no difference in meaning between them.
There's a good explanation of the differences in use between the most commonly used prepositions of place on this page if you're interested.
All the best
Kirk
The LearnEnglish Team
Thank you for the link concerning prepositions.
Sir,
Could you tell me the difference between, "When would you come tomorrow?" and "When will you come tomorrow?"
Thank you.
Hello Girikumar
Could you please search our site for an appropriate page to ask your questions? For example, in this same Verbs section, there is a page called 'will' and 'would'. I expect the explanation there will answer question, but if not, please feel free to ask us. We just ask that you try to ask your question on a relevant page.
All the best
Kirk
The LearnEnglish Team
Thank u for the reply. I will ask questions on the relevant page in future.
Hello Sir,
As usual I am in need of your help to understand the subtle differences between "sure of" and "sure about", "confident of" and "confident about". Despite the fact that I use them correctly, I tend to confuse them with the other ones at times. Thank you, sir.
Hello GIRIKUMAR,
As far as I am aware there is no difference in meaning between sure of and sure about. I don't know of any context where only one would be correct, though there are certain phrases where one is preferred, such as when using a reflexive pronoun (sure of yourself rather than about).
Peter
The LearnEnglish Team
Hello Sir,
1) kill him before he can kill you.
2) kill him before he kills you.
Is there any difference between these two sentences. If yes then what meaning two sentences convey.
Thank you.
Hello Abhinav,
In most contexts, the sentences can be used interchangeably.
Can carries the meaning of 'has the ability to', so you could imagine a situation in which you want to stop a person getting the ability to kill. For example, you might want to act so that someone is prevented from getting hold of a weapon which would make it possible for him to kill you.
Peter
The LearnEnglish Team
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