—The speaker is a tall man with glasses.—Then it         be Mr. Smith, who is short and thin.

“No student,”the headteacher stressed, “_______ go out of the school after ten o’clock at night without my permission. ”

—Mike’s parents have bought a 2-floor house with a swimming pool.— Oh, it________ be very expensive.

----Mum, ____ I watch TV now? ----No, you ____. You _____ finish your homework first.

--- He worked out such different questions at a very young age.--- Oh, he ______ a very smart student then.