Robert is indeed a wise manOh, yes. How often I have regretted his advice!A. to

--- Robert is indeed a wise man.
--- Oh, yes. How often I have regretted his advice!
A. to take
B. taking
C. not to take
D. not taking

A. to take B. taking C. not to take (答案→)D. not taking解析：考查单词regret，regret doing sth意思“后悔做过某事”，其否定形式regret not doing sth；regret to do sth意思“后悔做某事”，句子意思“我后悔没有听取他的建议”，所以选D

我明天再问问老师，叫他解释下这个问题