underground part的用法和樣例：
例句
- The roots are the underground parts of the tree that supply it with nourishment.
樹(shù)根是樹(shù)的地下部分，用于供應養分。 - Effect of laser process Chinese pine on the seedling growth of both aerial and underground part is studied.
研究了用激光處理油松種子對其幼苗地上部分和地下部分的影響。
