iron rust

例句：

1. 1. The old iron door is covered in rust.
   那扇旧铁门上满是锈迹。
2. 2. The car's engine has rusted over the years.
   这辆车的引擎多年来已经生锈了。
3. 3. The metal parts need to be polished to remove the iron rust.
   金属部件需要打磨以去除铁锈。