In land animals, saliva contains mucus, and provides lubrication for food in the alimentary canal.陆上动物的唾液内有粘液, 并对消化道内的食物起着润滑作用.In metal lubrication two distinct regions are recognized: boundary and hydrodynamic.在金属的润滑作用中...
Lubrication reduces noise and wear.润滑作用能减少噪音和磨损.We shall require more lubrication oil this month.这个月我们需要更多润滑油.Sludge can also clog oil passages and prevent normal engine lubrication.油泥还会阻塞油路,妨碍发动机的正常润滑工作....