A:SO2+H2OH2SO3
B:Cl2+H2O=HCl+HClO
C:3Fe+4H2O(g)Fe3O4+4H2
D:2Na+2H2O=2NaOH+H2↑
下列命题是真命题的是( )
Mum asked children to eat it ____ (two) a week.
____
下列历史人物与相关史实的搭配,正确的是( )