Underground car井下汽车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 sighting vane地下目标物Underground oil pipelines埋地输油管道Underground Water Quality地下水水质underground cavity survey井下空硐测量underground drilling unit巷道钻underground water dynamic地下水动态underground pipe-linein地下管线underground store-house地下仓库underground power station地下电站,地下式电站underground railway train地下铁道列车