单项选择题
A.2Na2SO3+O2=2Na2SO4B.NaOH+HCl =NaCl +H2OC.2CO+O2=2CO2D.2H2+O2=2H2O
A.越明显B.越快C.越好D.越差
A.60%B.70%C.80%D.90%