rust of apple

例句：

1. 1. The old car's engine has a lot of rust on it.
   这辆旧车发动机上有很多锈。
2. 2. The metal parts were badly rusted by the salt water.
   这些金属部件被盐水严重锈蚀了。
3. 3. Rust is a natural process that occurs when iron and oxygen come into contact.
   锈是一种自然过程，当铁和氧气接触时会发生。