(as) keen as mustard

• 极热心的；非常感兴趣的；(对…)非常着迷

(as) keen as mustard的用法和样例：

例句

1. He is keen as mustard in his work.
   他对自己的工作非常着迷。
2. And he seemed quite struck with Jane as she was going down the dance.
   当吉英走下舞池的时候，他可就显得非常着迷了。