短語(yǔ)詞組短語(yǔ)plumb -bob vertical [測(cè)][地物]鉛垂垂線(xiàn)Gage plumb -bob 垂球水尺Plumb -bob collimation 鉛錘視準(zhǔn)測(cè)量Line plumb -bob 錘線(xiàn) 返回 plumb-bob