A.15mg/L,0.5mg/L B.20mg/L,1mg/L C.25mg/L,1.5mg/L D.25mg/L,0.5mg/L
A.<50 B.50~100 C.100~150 D.>150
A.<1g/L B.10~20g/L C.>20g/L D.1.5~2.5g/L;