Polite requests & permission: Can / Could / May

Rules

• Rule 1: Requests → Can you / Could you

  To ask someone to do something we say Can you…? or the politer Could you…?. A base verb follows. Here could is not past tense; it just makes the request more polite.

  Pattern: Can / Could you + base verb (+ please)?

  Example: Can you close the window, please?

  Example: Could you help me with my homework?

• Rule 2: Permission → Can I / Could I / May I

  To ask permission we use Can I…?, Could I…? or the most formal May I…?. May I / Could I sound politer to teachers and adults.

  Pattern: Can / Could / May I + base verb (+ please)?

  Example: Can I play outside?

  Example: Could I borrow your ruler?

• Rule 3: Answers

  Yes: Sure. / Of course. / Yes, you can. No: Sorry, I can't. (to a request) / No, you can't. (to permission). It is polite to add a short reason. Reply to thanks: You're welcome. Even after “Could I…?”, we usually give permission with Yes, you can.

  Pattern: Sure. / Of course. · Sorry, I can't. · No, you can't.

  Example: Can I use your pen? — Sure, here you are.

  Example: Could you help me? — Sorry, I can't. I'm busy.

• Rule 4: borrow / lend

  borrow = take something for a short time (Can I borrow…?). lend = give something for a short time (Can you lend me…?).

  Pattern: Can I borrow your …? · Can you lend me your …?

  Example: Can I borrow your book?

  Example: Could you lend me your book?

Common mistakes

• May you help me? → Could you help me?

  May is only for permission with I / we; for requests use Can / Could you.

• Can I to open the window? → Can I open the window?

  No “to” after a modal; the verb stays in the base form.

• Can you borrow me your pen? → Can you lend me your pen?

  Giving → lend; taking → borrow.