He sharpened the edge of his knife on a grindstone. 他在磨石上磨快了他的刀刃。
We suggest sharpening on a wet stone because it cleans the pores of the sharpener dissipates frictional heat and facilitates smooth sharpening action. 我們建議使用一塊弄濕了的磨石,因為研磨液體能幫助清潔磨具上的孔,能散去摩擦產生的熱量,還能使磨刀的動作更加順滑。