单项选择题
A.硅酸根、电导率B.PH 、电导率C.磷酸根、电导率D.磷酸根、PH
A.10ug/L;24B.20ug/L;24C.25ug/L;24D.15ug/L;24
A.大于;48B.小于;24C.大于;4D.大于;2