在△ABC和△A′B′C′中，AB=A′B′，∠A=∠A′，若证△ABC≌△A′B′C′，还要从下列条件中补选一个，错误的选法是 [ ]

A．∠B=∠B′

B．∠C=∠C′

C．BC=B′C′

D．AC=A′C′

— Did you go to his birthday party last night?      

— No, I____, but I had some extra work to finish.       [ ]

A. must have     

B. could have        

C. could          

D. ought to