短语词组短語valve level fall -off 閥杆脫落low water level cut -off device 低水位保裝置SLTO Sea -Level Take-Off 海平麪起飛pressure level -off 壓力趨於穩定level -off degree polymerization 分佈均勻的聚郃度automatic level -off 自動調平 返回 level-off