问题
选择题
Although he talked half an hour, he couldn't give us a good ________ of the reason why he did it.
A．idea
B．explanation
C．sense
D．understanding
答案
答案：B
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.