The reason he explained for his being late was his alarm clock didn’t work.A. why; becau

问题补充：

The reason he explained for his being late was his alarm clock didn’t work.

A. why; because

B. that; because

C. /; that

D. for which; that

答案：

A. why; because

B. that; because

(答案→)C. /; that

D. for which; that

解析：第一空为定语从句先行词是The reason关系词要在从句中做explained的宾语所以要用关系代词which\that还可省略；第二空考查表语从句不缺成分用连接词that，所以答案为C