1, the mainstay, Chinese words, the mainstay refers to the delicate whetstone, sharpening refers to the rough whetstone. Sharpening refers to the whetstone, but also refers to the refinement exercise, used to express the revolutionary will, but also can be expressed in mutual encouragement.

2, sentence-making students should sharpen each other, exhort each other.

3, sharpening is extended to grinding chain. Repair service ": sometimes repair, sharpening and grinding hard, do not see its loss.