—How much shall I pay for the telephone call? —You  _____. It's free.

--- The task is challenging and demanding. Who do you think can make it? --- _______ my partner have a try? I think she is the right person to do it.

—Look! Is that Mr. Green?—It          be Mr. Green. He has gone to Shanghai.

Cheating is strictly forbidden in this important exam, and students ______ bring any reference books into their classrooms, cell phones included.

Johnny, you _________play with the knife, you_________ hurt yourself.