platform stair

例句：

1. 1. The architect designed a platform staircase that leads to the roof.
   建筑师设计了一段通往屋顶的楼梯。
2. 2. The elderly lady uses a platform staircase to access her apartment.
   这位老太太使用一个平台楼梯来到达她的公寓。
3. 3. The construction workers were busy installing platform stairs in the basement.
   建筑工人忙于在地下室安装平台楼梯。