can, could and could have


Questions and negatives:

We make questions by putting the subject after can/could:

Can I …? Can you …? Could I … Could you …? and so on.

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.
We sometimes say could not.

We use can and can’t :

  • To talk about ability:

Maria can speak four languages.
I can’t swim, but my sister can.

  • To say that something is possible or impossible:

Learning English can be difficult [= Learning English is sometimes difficult.]
Children can be very naughty [= Children are sometimes very naughty.]
It’s still light. It can’t be bedtime.

  • For requests and refusals of requests

Can I go home now?
You can go whenever you like.
You can borrow the car today, but you can’t have it tomorrow.

  • To offer to help someone:

Can I help you?
Can I carry that bag for you?

We use could and couldn’t as the past tense of can/can’t:

  • To talk about ability:

I could run very fast when I was younger.
She couldn’t get a job anywhere.

  • To say that something was possible or impossible:

Our teacher could be very strict when we were at school. [= Some teachers were very strict.]
People could starve in those days. [= People sometimes starved.]
You couldn’t use computers in the nineteenth century.

  • To make a polite request:

Could I go now please?
Could you lend me a dictionary please?

  • To make a polite offer:

Could I give you a lift?
I could carry that for you.

We use could have:

  • to show that something is possible now or was possible at some time in the past:

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




Hi Learner S,

'Could' is the past form of 'can'.  It is a modal verb and though it can have a present meaning, as in your example, it is formally a past form.  This is because in English we use past forms for more than just past time.  We can use them to show politeness ('Could you pass me the sugar?' is a little more polite than 'Can you pass me the sugar?'), to show that something is not likely ('If you could help me, that would be great' is less certain than 'If you can help me, that will be great'), amongst other uses.  That is why talking about 'could be' as a present tense is not accurate.

To learn more about different modal verbs, including 'could', visit this page.  You'll see links there to pages about specific modals and meanings.

Best wishes,



The LearnEnglish Team

sir, i m confuse about where to use would and would have
could you plz guide me ???

Hello OsamaAnischawla,

Your question was answered the first time you asked it (see further down the page).  Please post questions once only - sometimes it takes us a little while to answer them, but we can't do it any quicker, no matter how many times the question is asked.

Best wishes,



The LearnEnglish Team

Could anyone please explain can we use could be in present tense..............

Hi Learner S,

Could you please give an example of what you mean? could has many uses and meanings, and I'll be able to answer your question better if I understand what you're asking.

Best wishes,

The LearnEnglish Team

Hello OsamaAnischawla,

'Would' is one of the modal verbs in English and can be used in a number of different ways.  To investigate modal verb and their various meanings and uses, go to this page and work through the pages which are linked near the top, including one on modals + have.

I hope those links help to clarify it for you.

Best wishes,



The LearnEnglish Team

Hello there!

He could be the next champion.
It could be very cold in winter.

Are those two sentences describing future time?

Thank you.

Hello bimsara,

The sentences can be seen as describing both a present possibilty (he has now the potential to be the next champion) and a future possibility (when he will or may be champion) - it is very much a question of how you look at it.  In a sense, all sentences which describe probability or possibility reference the future, but they are also describing a present state (potential).

I hope that helps to explain it for you.


Best wishes,



The LearnEnglish Team

I am confused how to use shall / will, please help me