Can : It can rain.

Could : My brother could speak English when he was five.

May : May I call her?

Must : You must be here before 7 a.m

Have to : I have to stop smoking. My doctor said that.

Will : Tomorrow will be sunny.

Should : You should call her.

Ought to : You ought not to eat candy at night.

can('t):có thể:You can't park here.

could(n't):có thể:She could sing very well.

had better(not):nên:Children had better go to bed early.

must(n't):nên:You must obey your parents.

ought (not) to:nên:You ought to go to the doctor.

should(n't):You shouldn't play with knife.

may:có thể:He may at school.

might:có thể:She might have been at school.

will:sẽ:He will visit his parents next week.

have/has to:phải:Students have to wear uniforms at school.