There are several ways of asking, giving, and refusing permission.
If you want to ask permission to do something, you can use 'Can I...?' or 'Could I...?' (You use we instead of I if you are speaking on behalf of a group.) 'Could I...?' is more polite.
Can I light the fire? I'm cold.
Could we put this fire on?
Could I stay at your place for a bit, Rob?
You can add please to be more polite.
David, can I look at your notes please?
Good afternoon. Could I speak to Mr Duff, please.
Could you ask for them to be taken out, please.
You can also make your request very polite by adding perhaps or possibly after 'Could I' or 'May I'.
Could I perhaps bring a friend with me?
May I possibly have a word with you?
You can ask permission in a stronger way by using can't or couldn't instead of 'can' or 'could'. You do this if you think you may not be given the permission you want.
Can't I come?
Couldn't we stay here?
There are other, more indirect, ways of asking for permission to do something. You can use expressions such as 'Would it be all right if I...?' and, more informally, 'Is it okay if I...?'
Would it be all right if I used your phone?
Is it all right if I go to the bathroom?
Is it okay if I go home now?
In very informal situations, these expressions are often shortened so that they start with the adjective. This sounds more casual, as if you are assuming the other person will give their permission.
Okay if I smoke?
An even more indirect way is to say something like 'Would it be all right to...?', using a to-infinitive.
Would it be all right to take this?
A more polite way is to say 'Do you mind if I...?' or 'Would you mind if I...?'
Do you mind if we discuss this later?
Would you mind if I just ask you some routine questions?
Again, these expressions are shortened in very informal situations.
Mind if I bring my bike in?
You can also say 'I was wondering if I could...' or 'I wonder if I could...'.
I was wondering if I could go home now.
I wonder if I could have a few words with you.
In formal situations, you can add if I may after stating your intention to do something. You do this when you do not think it is really necessary to ask permission but want to appear polite.
I'll take a seat if I may.
Giving someone permission
There are many words and expressions that you can use to give someone permission to do something when they have just asked you for it.
In informal situations, you can say 'OK' or 'All right'.
'Could I have a word with him?' – 'OK.'
'I'll be back in a couple of minutes, okay?' – 'All right'
'Sure' is slightly more emphatic, and is used especially by American speakers.
'Can I go with you?' – 'Sure.'
'Of course', 'Yes, do', and 'By all means' are more formal, and emphatic.
'Could I make a telephone call?' – 'Of course.'
'Do you mind if I look in your cupboard for extra blankets?' – 'Yes, do.'
'May I come too?' – 'By all means.'
If you are not very certain or enthusiastic about giving permission, you can say 'I don't see why not'.
'Can I take it with me this afternoon?' – 'I don't see why not.'
You can give someone permission to do something when they have not asked for it by saying 'You can...'. If you want to be more formal, you say 'You may...'.
You can go off duty now.
You may use my wardrobe.
The commonest way of refusing someone permission is to use an expression such as 'Sorry', 'I'm sorry', or 'I'm afraid not', and give an explanation.
'I was wondering if I could borrow a book for the evening.' – 'Sorry, I haven't got any with me.'
'Could I see him – just for a few minutes?' – 'No, I'm sorry, you can't. He's very ill.'
'I wonder if I might see him.' – 'I'm afraid not, sir. Mr Wilt is in a meeting all afternoon.'
If you know the other person very well, you can simply say 'No' or 'No, you can't', but this is impolite. In informal situations, people sometimes use even more impolite and emphatic expressions to refuse permission, such as 'No way' and 'No chance'.
You can show that you do not really want someone to do something by saying 'I'd rather you didn't'. You say this when you cannot in fact prevent them from doing it.
'May I go on?' – 'I'd rather you didn't.'
In British English, you can refuse someone permission to do something when they have not asked for it by saying 'You can't...' or 'You mustn't...'.
You can't go.
You mustn't open it until you get home.
Speakers of American English do not usually use 'You mustn't...'. They say 'Don't...' instead. British people also use 'Don't...'.
Don't eat all the cookies.
You can also use 'You're not' and an -ing form. This is informal and emphatic.
You're not putting that thing on my boat.
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