We a discussion with the teacher came to understand the problem better.A. holding B. he

问题补充：

We, a discussion with the teacher, came to understand the problem better.

A. holding

B. held

C. being held

D. having held

答案：

A. holding

B. held

C. being held

(答案→)D. having held

解析：句意：跟老师讨论之后，我们终于对这个问题有了更好的理解。非谓语动词与句子主语存在逻辑上的主动关系，故排除备选项BC。显然“讨论”与“明白”时间上有先后，所以要用现在分词的完成式。