问题补充：
----- Believe it or not, my sister and I are twins.
----Oh, you must have had the case you were taken for your sister.
A. which
B. whose
C. where
D. whom
答案：
A. which
B. whose
(答案→)C. where
D. whom
解析：考查定语从句的关系词。 当先行词为case, situation,point等抽象的地点名词，且在句中作状语时，关系词应是where.
