bottom on建立在
bottomn.底部;底端adj.底部的v.触底;打(基础)
bottom-hole assembly钻具组合
bottom discharge valve底部排料阀
bottom water reservoir底水油藏
bottom orifice outflow底孔泄流
bottom unheading valve焦化塔底阀
bottom lock lifter bar下锁销杆
bottom tooth thickness齿根截面厚
bottom frame residence底框住宅
bottom-mounted sonar海底声呐
bottom-up management上行式的管理