underground dam地下坝undergroundadj.地下的；秘密的adv.在地下；秘密地n.地下；地铁；地道；秘密活动underground pipeline地下管道underground car park地下停车场,地下停车站underground ore body地下矿体underground magazine地下仓库underground lighting地下照明underground policies地下保单underground entrance地下入口underground painting先锋派绘画underground disposal地下处理underground railroadn.地下铁道；(美国内战前)废奴主义者帮助奴隶逃跑用的地下逃亡道

1. The roots are the underground parts of the tree that supply it with nourishment.
   树根是树的地下部分，用于供应养分。
2. Effect of laser process Chinese pine on the seedling growth of both aerial and underground part is studied.
   研究了用激光处理油松种子对其幼苗地上部分和地下部分的影响。