单项选择题
A.20% B.40% C.50% D.80%
A.1.0x10-5~4.0x10-5mol/L B.3.0x10-6~6.0x10-6mol/L C.2.0x10-5~4.0x10-5mol/L D.1.0x10-6~3.0x10-6mol/L
A.0~0.2 B.0.1~0.3 C.0.3~1.0 D.0.2~0.8