arithmetic progression

例句：

1. 1. The teacher explained the arithmetic progression in the problem.
   老师解释了问题中的算术级数。
2. 2. The company's financial performance is a geometric progression of its profits.
   公司的财务状况是其利润的几何级数增长。
3. 3. This is a common pattern in many natural phenomena, where the arithmetic progression is used to describe the rate of change.
   这是许多自然现象中常见的模式，其中使用算术级数来描述变化率。