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...
He never allowed his work to impinge on his private life.他从不让他的工作妨碍私生活。I heard the rain impinge upon the earth.我听到雨密密麻麻泻在土地上.Rays light impinge upon the retina.光线射到网膜上....