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 catalytic gasification地下催化气化
underground diagenetic environment地下成岩环境
underground wireless communication井下无线通信
underground criminal investigation卧底侦查
underground air defense facilities地下人防
underground coal banker engineering井下煤仓工程
underground drinking water resource地下水资源
underground water level observation地下水位观测