问题
单项选择题
She'll never forget her stay there （）she found her son who had gone missing two years before.
A. that
B. which
C. where
D. when
答案
参考答案：D
解析：
考查定语从句的用法。her stay为先行词，可以理解为抽象的一段时间(她呆在那里期间)，when指代her stay在定语从句中做时间状语。