A.8% B.9% C.10% D.12%
A.無積水 B.基礎(chǔ)牢固、通道無障礙、有防滑措施并設(shè)置護欄 C.寬度不應小于0.5m D.危險地段應設(shè)置警示標志或警戒線
A.低于0.5m B.低于3m C.低于2m D.低于1m