The reason he gave for being late was he forgot to set the alarm clock.A. which; because

问题补充：

The reason he gave for being late was he forgot to set the alarm clock.

A. which; because

B. why; because

C. which; that

D. that; because

答案：

A. which; because

B. why; because

(答案→)C. which; that

D. that; because

解析：考查定语从句和表语从句：第一空是定语从句，先行词是the reason，定语从句中gave缺少宾语，用that或which引导定语从句，第二空是表语从句：表示…的原因是…要用句型：(one)reason(for...)is that...句意：她迟到的原因是她忘记设定闹钟了。选C。