over and-under relay过和低继电器
over-under containment上下型安全壳
over-under squeeze高低挤牌法
Over-Under Position高低位
over-goodd-under抱异名腿背下握同名腕压桥
over-and-under抱异名腿背下握同名腕压桥
over-thed-under抱异名腿背下握同名腕压桥
over-or under-use过度或过少使用
Over-under-excavated values超欠挖
ADJ（形容词） (of a two-barrelled firearm) having one barrel on top of the other (双管枪)叠排式的
N（名词） an over-under firearm 叠排式双管枪