9163楼梯梯井的宽度一般为:()A.60~100mmB.100~150mmC.150~200mmD.200~250mm4390

楼梯梯井的宽度一般为:() A.60~100mm B.100~150mm C.150~200mm D.200~250mm 请帮忙给出正确答案和分析,谢谢!

答案解析