问题补充：
Mr. Hopkins has not yet answered my question I can go with him tohe calls the Underground Treasure House next week.
A. that; which
B. that; where
C. whether; that
D. whether; what
答案：
A. that; which
B. that; where
C. whether; that
(答案→)D. whether; what
解析：考查名词性从句。句中where引导同位语从句，解释说明名词question。what 可以在其引导的名词性从句中充当主语，宾语，表语，定语等句子成分。如你的句子.......what he calls the underground treasure house 中，what 位于介词to 的后面，引导宾语从句，并且，what 在宾语从句中充当calls 的宾语。选D。
