The day______ I shall never forget is the one _______ I joined t

The day______ I shall never forget is the one _______ I joined the army.
A、that… where
B、when. . . in which
C、which. . . when
D、on which. . . why
【正确答案】：C
【题目解析】：“I should never forget”和“I joined the army”都是定语从句。选择引导定语从句的关联词要看先行词在定语从句中作什么成分。先行词day在其后的定语从句中作forget的宾语，所以要用关系代词引导。而因为在定语从句“I joined the army”中，主语和宾语都有，是完整的主谓结构的句型，所以t．heone在其后的定语从句中只能作状语，这样就要用关系副词来引导，以使用 when。