underactv.不充份地表演；不卖力地演underprep.低于；在 ... 下；在 ... 内；在 ... 控制下adv.在昏迷中；在 ... 下adj.下面的；从属的；少于的underfed children/animals食物不足的儿童/动物Underfloor radiation heating地板辐射采暖under Command Administration受控于司令部管辖undercurrent circuit breaker欠电流断路器,欠电料路器underslung worm transmission下置蜗杆式传动under the seal of confidence约定保守秘密under ground drainage system地下排水系统underlying topological space基础拓扑空间undersell the competition.低价出售竞争under asymmetric information不对称信息