The reason he didn't e was he had to take care of his sick mother.
A. why ; that
B. why ; which
C. which ; why
D. that ; for
网友回答
(答案→)A. why ; that
B. why ; which
C. which ; why
D. that ; for
解析： 本题是一道定语从句与宾语从句的交叉考查。why引导的从句作为句中的定语，that引导的从句作为句中的宾语。