Is this the reason at the meeting for his carelessness in his work?A. what he explainedB.

问题补充：

Is this the reason at the meeting for his carelessness in his work?

A. what he explained

B. why he explained

C. he explained

D. how he explained

答案：

A. what he explained

B. why he explained

(答案→)C. he explained

D. how he explained

解析：考察定语从句。本题定语从句的先行词是the reason，that/which指代先行词做动词explain的宾语。因为做宾语，该关系代词可以省略。句意：这就是他在会议上对于自己在工作中的粗心解释的理由吗？故C正确。