Can Could May Might Must

Can

Can – for ability
I can dance Tango.
She can't sing.
Can you speak English?

Can – for permission
Can I sit here?
Can we leave now?
Can I play some music?

Can – for requests or suggestions
Can we have more coffee?
Can I have the bill?
You can go wherever you like.

Could

Could – past ability
I could run ten kilometres when I was younger.
We could see the ocean from our hotel room.
I could see that Danny was angry.

Could – for permission (polite)
Could I have another coffee?
You could sit here if you like.
Could you repeat that again?

Could - for possibility
This holiday could be really good.
You could go to the hairdresser tomorrow.
Could this really be true?

May

May – for formal permission.
May I come in?
May I make a suggestion?
May he ask a question?

May – to suggest a possibility
It may rain this evening.
They may be late.
He may agree with you.

Might

Might – for possibility
The electrician might be finished by tomorrow.
It might be bad weather tomorrow.
Peter might come to the party.

Must

Must – to express a formal request or necessity
I must finish the report today.
Each individual must help to stop pollution of the environment.
Every car must have seat belts.
He must give us a reply this morning.

Must – to show that something is very possible
She must be very intelligent.
There must be a lot of traffic. That's why they're late.
You must be tired after your journey.