– Must I stay here with you?-- No, you ______. You may go home, but you _____ go to the net bar(网吧).

  —The winner is a tall and thin boy with glasses!—Well，it________ be Mike.  He doesn’t wear any glasses.

The man over there _________ be over fifty. He looks so young.

No student______ go out of school for snacks during the break without the teacher’s permission.

---I have sore eyes.  ---You _____ play computer games too long.