as hard as nails的用法和樣例：
例句
- That hard-as nails young man was a sailor to the tips of his fingers.
那身體結實的年輕小伙子是個地地道道的水手。 - They are merciless, with hearts as hard as nails.
他們冷酷無情，鐵石心腸。 - He is as hard as flint where business is concerned.
他在生意上是冷酷無情的。
詞匯搭配
- hard as nails 鐵石心腸
