题目(单选题)窄狭坑道应设置爬梯,梯阶距离不应大于()。A. 10cmB. 20cmC. 30cmD. 40cm(单选题)窄狭坑道应设置爬梯,梯阶距离不应大于()。A. 10cmB. 20cmC. 30cmD. 40cm题目解答答案D. 40cm