--What's this? --It's__ backpack. --Where's__ backpack?--It's on the bed.
—Are there _______ halls in the building? —Yes, there are _______.
----________ is your friend ? ----He is a worker .
----- Is this ______ art room? -----Yes, it is.
_________ is my teacher, Mr. Li.
----- _______ is your English teacher? ------Mrs. Wang.