three over four roller drafting

例句：

1. 1.The three-roller four-roller mill is used for processing various materials.
   三辊四辊轧机用于处理各种材料。
2. 2. The three-roller four-roller mill is an important equipment in the steel industry.
   三辊四辊轧机是钢铁工业中的重要设备。
3. 3.The three-roller four-roller mill is widely used in metallurgical and chemical industries.
   三辊四辊轧机在冶金和化工行业中得到了广泛应用。