epithelium of guard

例句：

1. 1. The epithelium of the skin is responsible for protecting it from environmental damage.
   皮肤的保护层负责保护皮肤免受环境损害。
2. 2. The engineer designed a new material that provides an epithelium of protection against fire.
   工程师设计了一种新材料，可以提供对火灾的防护。
3. 3.The researchers found that the epithelium of the eye could be used to detect early signs of age-related macular degeneration.
   研究人员发现眼睛的保护层可以用来检测与年龄相关的黄斑变性的早期迹象。