Permission: can, could, may, might, be allowed to
Asking for, giving and refusing permission: Can I …?
We use can to ask for and give permission.
- ‘Can I ask you something?’ ‘Yes, of course you can.’
- You can go now if you want to.
Cannot/can’t are used to refuse permission (often with other words to soften the refusal).
- ‘Can I have some more cake?’ ‘No, I’m afraid you can’t.’
We also use could to ask for permission; it is more polite or formal than can. We do not use could to give or refuse permission (it suggests respect, so is more natural in asking for permission than in giving it).
- ‘Could I ask you something?’ ‘Yes, of course you can.’ (not
… of course you could.)
May and might are also used to ask for permission, and may to give permission. They are more formal than can/could, and are less common. Might is very polite and formal, and is mostly used in indirect question structures.
- May I switch on the TV?
- I wonder if I might have a little more cheese?
May not (but not might not) can be used to refuse permission.
- ‘May I smoke?’ ‘I’m sorry, you may not.’
There is an old belief that may/might are more ‘correct’ than can/could in these uses, but this does not reflect actual usage.
Must not (see here) can also be used to refuse permission; it is more emphatic than can’t /may not.
Talking about permission: Can everybody …?
Can is used to talk about permission that has already been given or refused, and about things that are allowed by rules or laws. May is not normally used in this way.
- Can everybody park here? (not
May everybody park here?)
Past permission: could is not always possible
In talking about the past, we use could (but not might) to say that somebody had permission to do something at any time (‘general permission’), but we do not use could to talk about permission for one particular action in the past. Compare:
- When I was a child, I could watch TV whenever I wanted to.
- Yesterday evening, Daniel was allowed to watch TV for an hour. (not
… Daniel could watch TV for an hour.)
But could not can be used to talk about one particular action.
- Daniel couldn’t watch TV yesterday because he was naughty.
(The difference between could and was/were allowed to is similar to the difference between could and was/were able to. (see here).)
Indirect speech
Can, could, may and might can however all be used to report the giving of permission (general or particular). Can/may are used after present reporting verbs, and could/might after past verbs.
- She says we can park here.
- They told us we couldn’t go in yet.
- The manager says we may leave our coats in the waiting room.
- Mr Newson agreed that I might look round. (very formal)
be allowed to
Modal verbs have no infinitives or participles. When necessary, permission is expressed in other ways: for example with forms of be allowed to.
- She’s always been allowed to do what she liked. (not
She’s always could …)