这座豪宅有一座宏伟的大理石楼梯。

The mansion featured a grand marble ___staircase.

阁楼只能通过一个室外楼梯进入。

The attic is only accessible by an outside ___staircase.

他们匆忙从紧急楼梯下去了。

They hurried down the emergency ___staircase.