Modals

To express habits

My father would read me a story before bed time (past habits)

He used to be a Boy Scout. State which is not a habit in the present anymore.

to make requests

Would you pass me the salt?

to give advice

I should study for the test. I ought to study for the test

To express Lack of necessity

We do not need /have to go to class.

To express possibility

He can arrive on time. (It is possible).

Sam can't be hungry. (It is imposible)

He could/may/might be sick. (50% of possibilities)

Why wasn't Marie here. She may/might/could have been sick. (happen in the past)

To express ability

She can swim. She couldn't swim yesterday (past ability). She is able to swim.

To express obligation

All applicants must/have to take the entrance exam.

To express a strong advice

You must study to improve your grade.

To express logical asumption

You must be happy.

to express prohibition

You must not tell anyone my secret.

To express willingness

I’ll have breakfast, please.

to express likelihood

The coach told our team will win the game. (present/future prediction).

The teacher told me I would get a better grade in the test. (past prediction)

to express certainty

Kathy will do well on the test. (The speaker feel sure)