A.排水 B.護面 C.擋墻 D.危巖支頂
A.30°-40° B.40°-50° C.50°-60° D.60°-70°
A.1m/s-5m/s B.5m/s-100m/s C.100m/s-200m/s D.5m/s-200m/s