A.干溝最深,支溝次之,集水井最淺 B.干溝最淺,支溝次之,集水井最深 C.支溝最淺,干溝次之,集水井最深 D.支溝最深,干溝次之,集水井最淺
A.0.3~0.5 B.0.5~1.5 C.1.5~3 D.3~5
A.40%~50% B.60%~70% C.75%~85% D.85%~95%