A:H2S通入CuSO4溶液中:H2S+Cu2+=CuS↓+2H+
B:AlCl3溶液与Na2S溶液混合生成沉淀::2 Al3++3S2-=Al2S3↓
C:用惰性电极电解BaCl2溶液:2Cl-+2H2O 通电__ Cl2↑+H2↑+2OH-
D:用TiCl4制备TiO2的第一步反应:Ti4++ (x+2) H2O(过量) ⇌ TiO2·xH2O↓+ 4H+
_______ isn't afraid of swimming in the sea. ( )
圆柱的侧面展开后一定是长方形。