English — Permission and requests
To ask for permission use Can/Could/May I…? and to ask someone to do something use Can/Could/Would you…? The choice of modal signals how formal or polite you sound.
How it works
For permission, the subject is I (or we): Can I sit here? / May I come in? For a request, the subject is you: Could you help me? / Would you close the door? Can is neutral and everyday, could and may are more polite, and would you is a common, courteous way to ask for a favour.
Examples
| Question | Politeness | Typical reply |
|---|---|---|
| Can I open the window? | Permission — neutral, everyday | Sure. / Yes, of course. |
| Could I ask you a question? | Permission — polite | Of course you can. / Certainly. |
| May I use your phone? | Permission — formal, most polite | Yes, you may. / Please do. |
| Can you pass the salt? | Request — neutral, everyday | Sure, here you are. |
| Could you help me with this? | Request — polite | Of course. / No problem. |
| Would you close the door, please? | Request — polite, courteous | Certainly. / I'd be happy to. |
Good to know
Could and would are not past tenses here — they simply sound more polite than can. To refuse, do not say No, you couldn't; a permission is declined with I'm sorry, you can't or I'm afraid not, and Would you…? is answered with a plain yes/no, never Yes, I would.