已知酸性强弱顺序为H2CO2>>HCO3-,下列化学方程式正确的是( )
A:+H2O+CO2→+Na2CO3
B:+H2O→+NaOH
C:+Na2CO3→+NaHCO3
D:+NaHCO3→+H2CO3
Many drivers think the ____(收费) should be much lower.