According to the United Nations, an aging society refers to one 10 percent or more of the population is over 60, or 7 percent or more is over 65.
A. where
B. when
C. which
D. that
网友回答
(答案→)A. where
B. when
C. which
D. that
解析：这题考查定语从句的用法，先行词是one代指an aging society“一个老龄化社会”，定语从句中不缺主语，宾语，表语，所以填where。