All flowing water, though it appears to be uniform, is actually divided into extensive inner surfaces, or layers, moving against one another.所有流动的水体虽然从表面看来都是浑然一体，但实际上其内部分成许多广延的面，或者说层，彼此逆向运动。Grade A vegetables have to be uniform in size and without marks or blemishes.一级蔬菜必须大小相同，没有瑕疵。