extra fine steel

• 优质钢

extra fine steel的用法和样例：

例句

1. The factory produced more steel, and all of fine quality at that.
   工厂生产了更多的钢材，而且都是优质钢。
2. The blacksmith forged the machine parts with the finest steel.
   铁匠用优质钢锻造这些机器部件。