—What a nice camera!—Yeah. It _______ Beijing.
You_______ play with the knife. You ______ hurt yourself.
— It seems that Mr. Wu is standing there.— It ______ be him because he called me from Canada just now.
—Will you please answer the door? It ________ be your sister.—Sorry, I ________. I’m feeding the rabbit.
--- Listen! David is talking happily with his mother in the next room.--- It ______ be his mother. She has gone to Yunnan to be a volunteer doctor.
— Must I finish my homework now?— No, you ________. You can go home now.