coppering bit

例句：

1. 1. He useda coppering bit to drillholes in the wood.
   他用铜钻在木头上钻孔。
2. 2. The coppering bit wasrusted and needed to be replaced.
   铜钻生锈了，需要更换。
3. 3. The copperingbit was very sharp and made the jobgo quickly.
   铜钻非常锋利，使工作进展得很快。