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

问题补充：

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

A. he explained

B. what he explained

C. how he explained

D. why he explained

答案：

(答案→)A. he explained

B. what he explained

C. how he explained

D. why he explained

解析：考查短语从句。句中先行词为the reason,在定语从句中作explain的宾语，故省略关系词，选A。