—David，is that man your Chinese teacher?—It___________ be him．He’s having a meeting． 

---Whose is the pencil box?---It _____ be Tom’s. Look at his name on the cover!

You _________ to eat snacks in the classroom.

This book isn’t mine. ________can it be?

─ Is the woman in white our manager?  ─ It ________be her. She has just left for Shanghai.