underground root

例句：

1. 1.The tree's underground root is so deep that it can support the weight of a car.
   这棵树的地下根非常深，可以支撑汽车的重量。
2. 2. The roots of the plant are deeply buried in the soil.
   植物的根深深地埋藏在土壤中。
3. 3.The underground root system plays a crucial role in the plant's survival.
   地下根系统在植物的生存中起着至关重要的作用。