double-flap gate type feeder 双翻板阀供料器

double flap amputation 双瓣截肢术

Double Flap Gate Valve 双层翻版阀

double-flap valve 双瓣阀

double flap wave maker 双摇板造波机

Double flap reconstruction 双骨瓣成形术

Motorized Double Flap valve 电动双翻板阀

double slotted flap 双缝襟翼 ; 双开缝襟翼