can or could



We use the modal can to make general statements about what is possible:

It can be very cold in winter. (= It is sometimes very cold in winter)
You can easily lose your way in the dark. (= People often lose their way in the dark)

We use could as the past tense of can:

It could be very cold in winter. (=Sometimes it was very cold in winter.)
You could lose your way in the dark. (=People often lost their way in the dark)

We use could to show that something is possible in the future, but not certain:

If we don’t hurry we could be late. (=Perhaps/Maybe we will be late)

We use could have to show that something is/was possible now or at some time in the past:

It’s ten o’clock. They could have arrived now.
They could have arrived hours ago.


We use the negative can’t or cannot to show that something is impossible:

That can’t be true.
You cannot be serious.

We use couldn’t/could not to talk about the past:

We knew it could not be true.
He was obviously joking. He could not be serious.


We use can 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 to talk about the ability to do something at a given time in the present or future:

You can make a lot of money if you are lucky.
Help. I can’t breathe.
They can run but they can’t hide.

We use could to talk about past time:

She could speak several languages.
They couldn’t dance very well.



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 if you like.
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 free.

Instructions and requests:

We use could you and 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 and invitations:

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 can give you a lift to the station.




Hello B H A R T I,

'be' is a bare infinitive, which is the form used after 'can' and other modal verbs. 

All the best,
The LearnEnglish Team

Hello sir, will you tell me the difference between these two sentences
1 I will there
2 I will be there
and when we used 'be'.

Hello Bharti,

Sentence 1 is not correct. 'will' is a modal verb (like 'can' and 'could') and so in complete sentences it must be followed by a verb in the bare infinitive form. 'be' is one such bare infinitive; other bare infinitives (e.g. 'go', 'visit', etc.) are also possible there.

Best wishes,
The LearnEnglish Team

Hello sir, could you send me some links on bare infintive 'be' uses ?.and also I want to know how can I improve my english,I can not speak english well.If there is any grammatical mistake then please let me know.

Hello B H A R T I,

For tips on how to improve your English, try our Help page.

For guidance on different aspects of the verb system in English you could look at our Verbs grammar page. However, we don't have pages specifically on the bare infinitive 'be'. The bare infinitive is used in a huge number of forms and it would pointless to list them all - there are too many. It is not an organising principle of grammar. You can find links on the page mentioned above to many different forms which are followed by the bare infinitive, such as modal verbs, for example, or forms which may include 'be', such as some passive forms.

I hope that is helpful to you.

Best wishes,


The LearnEnglish Team

Hello sir,
What is the difference between
1.simple past and
2.past perfect tense
Please clear me where to use past perfect ?
Tank you

Hello Ajaz ajju,

We have several pages on this topic.

For information on the past simple - here.

For information on the past perfect - here and here.

Best wishes,


The LearnEnglish Team

Hello I write this in order for you to help me clarify this. what is the difference between these following sentences: Let the whole wold should be singing and Let whole world should sing.

Hello Lamastry,

I'm afraid that neither of these clauses are grammatical in standard English. Perhaps 'Let the whole word sing'?

Best wishes,
The LearnEnglish Team