【单选题】29 / 35锯齿形街沟主要用于纵坡小于多少的路段?A0.1%0.1\%0.1%B0.3%0.3\%0.3%正确C0.5%0.5\%0.5%D1.0%1.0\%1.0%参考答案B参考解析0.3%0.3\%0.3%。