Although he talked half an hour he couldn't give us a good of the reason why he did it.A

问题补充：

Although he talked half an hour, he couldn give us a good of the reason why he did it.

A. idea

B. explanation

C. sense

D. understanding

答案：

A. idea

(答案→)B. explanation

C. sense

D. understanding

解析：选择B。根据句意：他谈了半个小时，但就那件事，仍未能给出一个合理解释。

explain,名词为explanation.