A.先上游排孔,后中間排孔,最后下游排孔 B.先下游排孔,后中間排孔,最后上游排孔 C.先下游排孔,后上游排孔,最后中間排孔 D.先中間排孔,后下游排孔,最后上游排孔
A.6% B.7% C.5% D.10%
A.0.3~0.4 B.0.3~0.5 C.0.3~0.7 D.0.4~0.7