kerato-

例句：

1. 1. The skin on his face is very kerato.
   他脸上皮肤非常硬。
2. 2. The nail is kerato and needs to be filed down.
   指甲很硬，需要磨平。
3. 3. The plant has a kerato layer that protects it from the sun's harmful rays.
   这种植物有一层硬皮，可以保护它免受太阳有害射线的伤害。