A:Mg2++2OH-=Mg(OH)2↓ MgSO4+Ba(OH)2=Mg(OH)2↓+BaSO4↓
B:Fe+Cu2+=Fe2++Cu Fe+Cu(OH)2=Fe(OH)2+Cu
C:Ag++Cl-=AgCl↓ AgNO3+HCl=AgCl↓+HNO3
D:CO2+2OH-=CO32-+H2O CO2+Ca(OH)2=CaCO3↓+H2O
下列城市在区域的发展中产生作用最大的是( )
—Joe, our daughter's birthday is next Sunday.—I want _______ her a computer.