1. Modal Verbs
Should – Ought to - Must

2. Should – advice, moral obligation, recommendation
You should stop watching TV.
Kate shouldn’t eat so much sugar.
Should teenagers respect their parents?

3. Ought to = should (mas mais enfático)
You ought to do your homework.
She ought not to fight with her sister.
Ought we to fight everyday?

4. Must – obligation, intense necessity, conclusion Must not/Mustn’t - prohibition
You must brush your teeth after meals.
My kids must wear heavy clothes in winter.
They must have gone, the lights are off.
It’s getting late, You must be tired.
You mustn’t eat fatty food.
They must not drive when you are drunk.

5. Have to – necessity Don’t have to – not necessary
I have to fix that TV.
Nora has to clean their bedroom.
I don’t have to travel next weekend.
She doesn’t have to do her homework now.

6. Must in the Past = Had to Must in the Future = must/will have to
I had to do a lot of things yesterday.
She had to be there last month.
Daniel must attend to the meeting tomorrow.
Susan will have to work next weekend.