Can/ Could I? Can/Could you?

1.- We form questions with can, may and could like this:

Questions

Can
May --------> I/He/She/It/We (etc.) wait?
Could

2.- We use can, may and could to ask for things:

Can etc. + I/we + have ...?

Can I have a coffe?


Example

Could we have two tickets,please?
Can I have some sugar?

3.- We use can, may or could to ask for permission. Could I and May I are more formal and polite than Can I:

Can/May/ Could + I/We + INFINITIVE...?

Example:

Could we look at your map, please?
Can I borrow your tennis racquet, please?

We use can or may to give permission:
You can leave your bag here. (Or... may leave...)

If we talk about what is allowed in general, rather than by a particular person, we use can:

People can drive on the roads when they are seventeen.

But official notices often use may:
BAGS MAY BE LEFT HERE.

4.- We use Can you, Could you and Would you (but not May you) when we ask someone to do something. Could and would are more formal and polite than can.

Can/ Could/ Would + you + INFINITIVE ...?
Could you help me?

Example:

Could you buy me a newspaper?


A: I'm cold. Can you close the windows?
B: Yes, of course.