单项选择题
A.2400 B.2000 C.1500 D.1200
A.1/2 B.1/3 C.2/3 D.3/3
A.AL3+;Na+;OH- B.Ca2+;Fe3+;OH- C.Ca2+;Mg2+;OH- D.CL-;Mg2+;OH-