hairy sheath

例句：

1. 1. The animal's fur was so thick that it covered the entire body.
   这只动物的毛皮非常厚，覆盖了整个身体。
2. 2.The scientist found a hairy sheath on the surface of the skin.
   科学家在皮肤表面发现了一个毛皮层。
3. 3. The hairy sheath is essential for keeping the animal warm in cold weather.
   毛皮层对于动物在寒冷天气中保持温暖至关重要。