"he paused on the bottom step"
She..climbed the winding stair.
27 Duntarvie Quad was a solid sandstone tenement...The stair was clean and smelled of disinfectant.
Risks..caused by..objects left on the stairs.
牛津高阶第八版
美国韦氏词典
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维基百科 (自由的百科全书)