Modal affirmative sentences
must, have to, have got to
You must be a Asian at the way you look.
Modal negative sentences (strongly certain)
must not(mustn't), could not (couldn't), can not(can't)
Chef must be very good. (Restaurant is packed.)
2. Should/Ought to (medium)
He should be at home. It is 8 o'clock. (He always goes home at seven.)
Should not (shouldn't)
The food should be good. (The food is probably not good.)
She probably doesn't have so many friend.
She should drive Toyoto. (She lives in Japan.)
You should be loyal and love to your country.
3. Not very certain/sure/positive
may, might, could
He might be in a cafee.
may not, might not
Stomach is growling, she might be hungry.
1. Suggestion - could/might
2. Advice/opinion - should/ought to - shouldn't (should-more common used in question.)
3. Expectation - be supposed to - not to be supposed
4. Warning - had better - had better not (for past- should have)
5. Necessity/Obligation - must/have to/have got to - musn't
6. Prohibition - can not/can't