A.0.2 B.0.3 C.0.4 D.0.5
A.10B.15C.20D.25
A.三通型人孔 B.四通型人孔 C.斜通型人孔 D.手孔
A.2 B.3 C.4 D.5
A.0.2,0.1 B.0.4,0.3 C.0.3,0.5 D.0.3,0.4