manholes造句
This welding backing is specially designed for hand holes and
manholes welding.
本衬垫适用于入孔,出孔的焊接使用.
Air investigations are absolutely necessary before entering any
manholes.
空气调查是绝对必要的,方可进入任何沙井.
Interior surfaces of
manholes and its covers should level with that of the container.
人孔及人孔盖的内表面与容器的内表面平齐.