regrettable
regretful是“懊悔的，遗憾的”，regrettable是“令人遗憾的”，就是“可惜的”，下面各句里的regretful和regrettable不可对调：
- I am regretful for it.
- He made a regretful apology.
- This is a regrettable error.
- It is regrettable that they have left the city already.
- He made a regrettable mistake a year ago and has since been regretful.
