实现下列物质的转化方式，只有一种途径的是（　　）

A．CO→CO₂

B．Fe→FeSO₄

C．CuO→CuSO₄

D．CaCO₃→CO₂

----Did you go to the cinema last night?

----No, We    , but our car broke down on the way.

A．must have gone

B．shouldn’t have gone

C．could have gone

D．Needn’t have gone