chetrum

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 paint has turned to rust over the years.
   这辆车的漆已经变成了铁锈。
3. 3. The metal object has developed a rusty patina.
   这个金属物体已经长出了铁锈。