pao-ferro

例句：

1. 1. The old iron gate is covered in a thick layer of rust.
   那把旧铁门上覆盖着厚厚的一层铁锈。
2. 2. The car's engine was rusted and needed to be replaced.
   这辆车的引擎生锈了，需要更换。
3. 3. Rust can form on any metal surface that isn't properly protected from the elements.
   任何金属表面如果不妥善保护，都可能发生锈蚀。