Помогите пожалуйста с английским!!!
Fill the gaps using must, may или can’t.

It _____ be true. I don’t believe you!
Mike _______ be at the university right now. I saw him 10 minutes ago.
John _______ be a teacher. I don’t really know.
This _______ be my towel. I can’t recognize it.
She ______ be playing the piano now. I can hear music.
This milk _______ go off if you don’t put it into the fridge.
She _______ have been at the meeting when I called her.
They _______ left for London last week, they didn’t tell me.
She _______ have been running very fast. She was totally out of breath.
Helen has no friends. She _______ be very lonely.