A.<1NTU B.<2NTU C.<3NTU D.<5NTU
A.0.5μm B.1μm C.2μm D.5μm
A.8%~12%HCl溶液 B.10%NaCl+2%NaOH溶液 C.8%~12%NaOH溶液 D.10%NaCl+2%HCl溶液