Modal verbs of Permission

Level of formality

CAN < COULD < MAY

Asking for a permission

Can, Could, May

◦ Can I borrow your pen for a moment? - Sorry, I need it. Is the pencil OK?

◦ Could I take a look at your notes? - Yeah, sure​.

◦ May I go to the toilet, sir? - It's only ten minutes to go. You'll have to wait​

​

​The difference is in politeness and formality. Could tends to sound more polite than can, and may is more formal

Granting and refusing permission

Can/May and Can't/May Not

Could/Couldn't cannot be used to give or refuse permission - only to ask it and to talk about permission in the past.

• May is much less common than can in both granting and refusing permission orally, as it is more formal. May not, in particular, smells of authority.

• To express prohibition, must not may also be used

Granting and refusing permission

Can/May and Can't/May Not

• You can wait in the living room if you want.

• Could I borrow your rubber? - Sure you can.

• You may leave as soon as you finish the exam.

• Could we have a barbecue up in the park? - I'm afraid you can't -it's too dangerous.

• Candidates may not bring dictionaries.

• You mustn't leave your bags around on the airport​

Talking about permission

Can/Could, Be Allowed To

If we want to talk about permissions and rules made by third parties, by someone else, we cannot use may.

Can/Could can only be used in the Simple tenses (past and present). The other possible time forms (Future, Perfect) require be allowed to.

Talking about permission

Can/Could, Be Allowed To

I was allowed to / could stay up till ten when I was a kid.

Sometimes, she can / is allowed to take home some food from the restaurant she works in.

Can you take photos in here?

Could you enter the crypt? - No, visitors weren't allowed there back then. Nowadays, you can enter it if you're with a guide.