单项选择题
A.60~100mg/LB.30~60mg/LC.15~30mgD.10~15mg
A.硫化物、沼气B.有机酸C.铁铜等重金属D.A、B 和C
A.1000~2000mg/LB.2000~3000mg/LC.3000~4000mg/LD.4000mg/L