intestine and casing

例句：

1. 1.The intestine and casing are essential for digestion.
   肠子和套子对于消化至关重要。
2. 2. The intestine and casing play a crucial role in the body's immune system.
   肠子和套子在身体免疫系统中起着关键作用。
3. 3.The intestine and casing need to be cleaned regularly to prevent infections.
   肠子和套子需要定期清洁，以防止感染。