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

问题补充：

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

A. explained

B. what he explained

C. how he explained

D. why he explained

答案：

(答案→)A. explained

B. what he explained

C. how he explained

D. why he explained

解析：句意：这就是那个他在会议上解释的由于工作粗心的原因吗？explained at the meeting for his carelessness in his work这是定语，修饰the reason，它与explain之间是被动关系，故用过去分词。如果用定语从句必须用关系代词做explain的宾语，用that或which都行。故选A。