A.PH5.0-7.0 电导率≤20us/cmB.PH5.0-6.5 电导率≤20us/cmC.PH5.5-6.5 电导率≤10us/cmD.PH5.0-6.5 电导率≤10us/cm
A.5B.0.5C.1D.0.1