Can I open the window?
May I go to the washroom?
You should study more?
I can skate.
You don”t have to buy a new car.
She must move in two days.
I would rather sleep for a week.
You had better clean your room by the the time I come back.
- Requests: can, could, will, would
- Asking for permission: can, could, may, might
- Advice: might, should, could
- Commands: had better, must, will
- Logical probability: might, may, could, must
- Ability: can
- Expectation: should, ought to
- Lack of necessity: don’t have to
- Logical impossibility: cannot
- Necessity: must, have to
- Preference: would rather
- Prohibition: must not