Cuòguò le zhècì nándé de jīhuì, tā gǎndào fēicháng yíhàn.
Having missed this rare opportunity, he feels very regretful.
Tips
usage
遗憾 is softer than 后悔 (hòuhuǐ, to regret deeply). 遗憾 expresses 'it's a pity' or 'unfortunate,' while 后悔 implies self-blame for a wrong choice. 很遗憾 is a polite way to deliver bad news.
