feel blue
感到悲伤或沮丧
口语·形容情绪低落或悲伤
英文释义
to feel sad or depressed
例句
She's been feeling blue since her cat ran away last week.
典故来源
蓝色在西方文化中常与忧郁、悲伤相关联，源自19世纪航海传统，蓝色旗子表示船上有死亡或疾病。