1640s, "full of regret," from regret + -ful. Regretfully, properly "with regret," incorrectly used in place of regrettably "it is to be regretted that; calling for regret" since at least 1965. "A regrettable use, prob. after HOPEFULLY adv.2" [OED].
实用例句
1. Surprisingly, she didn't feel nervous, or regretful about her actions.
令人惊讶的是，她并没有对她的行为感到紧张或后悔。
来自柯林斯例句
2. Mr Griffin gave a regretful smile.
格里芬先生遗憾地笑了笑。
来自柯林斯例句
3. A person who does a regrettable action is often regretful afterwards.
