the main function of the small intestine

例句：

1. 1.The small intestine plays a crucial role in digestion.
   小肠在消化过程中起着至关重要的作用。
2. 2.The small intestine is responsible for absorbing nutrients from food.
   小肠负责吸收食物中的营养物质。
3. 3. The small intestine has a vital role in maintaining the body's balance of fluids and electrolytes.
   小肠在维护身体水分和电解质平衡方面起着至关重要的作用。