Modals of possibility and deduction

A: Who's at the door? B: I don't know; it _______ be John.

He ________ be at the gym right now. Sometimes he goes there at this time.

She _________ be in love with him. She told me she hates him.

This is not possible. You ________ be serious!

He __________ be in class. I saw him at the library a minute ago.

You should pick up the phone. It ________ be an important call.

The phone is ringing. It ________ be Charlotte; she said she would call this morning.

You _________ be right, but it's better if we check.

He _______ know the answer, he's the best in the class.

If he drives a jaguar, he _________ be quite rich.