排头兵: bellwether vanguard; bellwether;vanguard; pioneer排头坑: pai tau hang排头路: pai tau lo石排头: shek pai tau在排头: at the head of分排头文件: batch-header document位居排头: be at the head of a queue中断排头指示字: interrupt queue head pointer排筒机构: empty case ejector mechanism排通道: exhaust passage排烃效率: expulsive efficiency排图法: array diagram method排替压力: displacement pressure; replacement pressure排土: casting◇排土场 refuse dump; spoilbank排题板;转换板;插塞板: problem-board