问题补充：
Europe has achieved more in controlling the AIDS virus than Asia in the past ten years, the number of people infected with the virus is going up sharply.
A. when
B. which
C. that
D. where
答案：
A. when
B. which
C. that
(答案→)D. where
解析：考查定语从句关系词的选择。 本题关键在于找准定语从句所修饰的先行词，根据句意可知，此处先行词为Asia，在后面从句the number of people infected with the virus is going up sharply中做地点状语，故选择D
