—Will you buy me a new iPod, Dad?—OK. You __________have one if you promise to take care of it. 

— Listen! Helen is singing in the classroom.—It _______ be Helen. She has gone to Shanghai.

— Can I go to the movie, Mum?— Certainly. But you _______ be back by ten o’clock.

She can hardly write her own name, ______?

A hard-working man _____ become a great scientist, but a great scientist _____ be a hard-working man.