【题目】— Do you know ______ Mr. Black's address is.
— He may live at No.18 or No.19 of Bridge Street. I'm not sure of ______
A.where; which
B.where; what
C.what; which
D.what; where

【答案】C
【解析】句意: ——你知道布莱克先生的地址是什么吗？——他可能住在桥街18号或19号。我不确定是哪一个。第一个what“什么”引导宾语从句; which哪一个，故选C