A:Cu(OH)2+2HCl═CuCl2+2H2O
B:SO2+2NaOH═Na2SO4+H2O
C:2H2+O2═2H2O
D:2KMnO4 △_ K2MnO4+MnO2+O2
The Great Wall is one of ______ wonders (奇迹)in the world.