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。