1. May:
i) To make requests (formal) - May I sit down?
ii) To give permission (formal) - You may sit down.
iii) To show possibility - It's starting to get cloudy - it may rain soon.
2. Can:
i) To make requests (informal) - Can I sit down?
ii) To give permission (informal) - You can sit down.
iii) To express possibility (in general) - It can rain sometime.
3. Could:
i) To make requests (polite) - Could I sit down?
ii) To express possibility (weaker than "may") - It could rain but it is not common in this part of the country
4. Would:
i) To make requests (polite) - Would you mind if I sit down?
ii) To express possibility (weaker than "may") - It could rain but it is not common in this part of the country
5. Must:
i) To show obligation (full) - You must tell the police the truth
ii) To express logical conclusions (stronger than should) - He left an hour ago, so he must be there already
6. Should:
i) To show obligation (partial) - You must tell your friends the truth
ii) To express logical conclusions (weaker than must) - He left an hour ago, I believe he should be there already.
7. Ought to:
i) To show obligation (partial & less common) - You ought to tell your friends the truth
8. Might:
i) To express possibility (weaker than "may") - It's not very cloudy yet, but it might rain
9. Will:
i) To show future (actions/ states/ Intentions) - Look at the sky! It will rain soon
Doubts on this article
