A:点①所示溶液中: c(H+)/c(OH-)=1012
B:点②所示溶液中:c(K+)+c(H+)=c(HC2O4-)+c(C2O42-)+c(OH-)
C:点③所示溶液中:c(K+)>c(HC2O4-)>c(H2C2O4)>c(C2O42-)
D:点④所示溶液中:c(K+)+ c(H2C2O4)+ c(HC2O4-) +c(C2O42-)=0.10mol·L-1
—I don't know either.Why not________the meaning in the dictionary?