keen as mustard
非常熱衷、積極、有意愿
口語·形容非常熱衷
英文釋義
to be very eager or enthusiastic about something
例句
She's keen as mustard to start her new job next week.
典故來源
源自19世紀英國，芥末的辛辣比喻人的熱情和積極性。