短语词组短語backstop tone 後定位夾鉗hydraulic backstop 以液壓陞降的籃球架backstop plan 保障安排liquidity backstop 防止流動性枯竭backstop inside 內支撐塊backstop tongs 止退鉗;後擋鉗gearbox backstop 變速箱止廻器relay backstop 繼電器止档backstop welding 分段退銲 返回 backstop