楼梯 梯级 的复数 中释
The boy thumped down the stairs..小男孩咚咚地跑下楼梯。
The suitcase bounced down the stairs..衣箱一路颠跳着滚下楼梯。
The children pattered down the stairs..孩子们啪嗒啪嗒地跑下楼梯。
flight of stairs,阶梯步级
down stairs,下楼
