Definition: a set of steps which lead from one level of a building to another Level: A2
他每天都要爬五层楼的楼梯。
He has to climb five flights of ___stairs every day.
请使用楼梯，不要乘坐电梯。
Please use the ___stairs instead of taking the elevator.
我的书包在楼梯下面。
My schoolbag is at the bottom of the ___stairs.
