下列方程式中，属于水解反应的是（    ）

A．H₂O + H₂O H₃O⁺ + OH^—

B．HCO₃^— + OH^— ="" H₂O + CO₃^2—

C．CO₂ + H₂O H₂CO₃

D．CO₃^2— + H₂O HCO₃^— + OH^—

-- How far is it from here to the Great Wall?

-- About        in a car.

A．3 hours’ ride

B．3 hours’ walk

C．3 hours’ flight

D．3 hours