A.30-150mg/L B.100—350mg/L C.900—1750mg/L D.20-100mg/L
A.6.0-6.8 B.8.8-9.3 C.9-10 D.10-11
A.600-800us/c B.≤5us/cm C.≤0.2us/cm D.≤30us/cm