modal verbs

An action is not possible (because it is against the rules or for another reason).

• must

• can't

• musn't

• don't have to

An action is a good idea (advice/recommendation)

• can't

• don't have to

• may

• should

A situation is possible.

• must

• should

• may

• can

An action is not a good idea (Advice not to do something)

• must

• mustn't

• should

• don't have to

An action is not necessary. (There is no obligation)

• may

• don't have to

• mustn't

• can't

It refers to something which is necessary.

• must

• don't have to

• can't

• should

It is used about something which is wrong to do.

• can't

• don't have to

• may

• mustn't

It refers to something which is necessary ( must ), it is more common when talking about the law or company rules.

• have to

• should

• mustn't

• don't have to

Do you _________ wear a tie for school? (tie* corbata)

• may

• should

• have to

• must

You ______ go to the doctor if you are sick. (advice)

• don't have to

• should

• may

• can