a feather in one's cap不能简单地理解为“帽子上有羽毛”，实际意思是“荣誉，成就，值得自豪的事”。

【例句】
Winning the debate competition，was a feather in his cap.
赢得这次辩论赛是他的荣誉。

Getting published in a prestigious journal is a feather in any scientist's cap.
在一本声誉卓著的期刊上发表文章对任何科学家来说都是一种荣耀。