Tom regretted——good use of his spare time.A.not to have made B.not having made
问题描述：
Tom regretted——good use of his spare time.A.not to have made B.not having made
答
B.not having made
regeret doing表示对已经发生的事遗憾,
regret to do是对还没发生的事表示遗憾
题目中是说对自己以前浪费时间遗憾,是发生过的,用doing ,后面也要用完成时