sharp iron

例句：

1. 1. The knife is sharp enough to cut through a piece of steel.
   这把刀足够锋利，能切断一块钢。
2. 2. He has sharp eyes that can spot any mistakes in the report.
   他的眼睛很锐利，能发现报告中的任何错误。
3. 3. The sharp edge of the knife cuts through the paper easily.
   这把刀锋利的边缘很容易就切穿了纸张。