结硬皮

例句：

1. 1. The old tree had a hard skin that made it difficult to climb.
   这棵老树有一个坚硬的皮肤，很难爬。
2. 2. The car's dashboard has a hard skin that protects the electronics.
   汽车的仪表盘有一个坚硬的皮肤，保护电子元件。
3. 3. The leather jacket has a hard skin that makes it durable and long-lasting.
   皮夹克有一个坚硬的皮肤，使其耐用且经久不衰。