unenclosed exterior stair

例句：

1. 1.The architect designed the building with unenclosed exterior stairs for easy access.
   建筑师设计了这座建筑，其未封闭的外部楼梯便于通行。
2. 2. The construction workers were working on the unenclosed exterior stairway when it collapsed.
   施工人员在未封闭的外部楼梯上工作时，它突然坍塌了。
3. 3. The new apartment complex features a central courtyard with unenclosed exterior stairs connecting all floors.
   这个新的公寓综合体有一个中央庭院，连接所有楼层的未封闭外部楼梯。