— Listen! Is that Linda singing in the next room?— No, it ________ be her. She is still in Shanghai.
—Most paper is made________wood.—Yeah.But most books are made________paper.
Many overseas Chinese look forward to________more about their roots in the summer camp.
—Where did you get these old doors?—From the old houses which were________by the workers.
Things should________here before you enter the Great Museum.
—There are only a few old city walls left.—Yeah.Most of them________in the 1960s.