This is a long and tedious process in which the toolmaker repeatedly grinds away the stone with a harder material or with sand, sometimes using water as a lubricant.
英
美
- 但对于工具制造者来说,这却是一个长期而又单调的过程,他必须反复地用更坚硬的材料或是沙子打磨石头,有时还需要用水作润滑剂。