stair step

例句：

1. 1. The stair steps are worn smoothfrom years of use.
   这些楼梯台阶因为多年的使用而变得光滑。
2. 2. Theold house had a lotof stair steps that weredifficult to climb.
   这所老房子有很多楼梯台阶，很难爬。
3. 3. The childrenloved to play on the stairs and stepup and down.
   孩子们喜欢在楼梯上玩耍，上上下下。