The reason she didn’t come to school wasshe had to look after her sick mother.A. because ;

问题补充：

The reason she didn’t come to school was

she had to look after her sick mother.

A. because ; why

B. that ; because

C. why ; that

D. which ;that

答案：

A. because ; why

B. that ; because

(答案→)C. why ; that

D. which ;that

解析：考查定语从句及名词性从句。考查the reason why … was that ……..的原因是……。Why引导定语从句，that引导表语从句，故选C。