有人设计出利用CH₄和O₂的反应，用铂电极在KOH溶液中构成原电池。电池的总反应类似 于CH₄在O₂中燃烧，则下列说法正确的是[ ]

①每消耗1mol CH₄可以向外电路提供8mol e^-

②负极上CH4失去电子，电极反应式为CH₄+10OH^--8e-==CO₃^2- +7H₂O

③负极上是O₂获得电子，电极反应式为O₂+2H₂O+4e^-==4OH^-

④电池放电后，溶液pH不断升高

A．①②

B．①③

C．①④

D．③④

— Isn't it a surprise that I happened to meet Emily at Doris' birthday party last weekend?

— If my memory serves me correctly, you _________ each other for exactly three years. [ ]

A. hadn't seen      

B. haven't seen  

C. didn't see    

D. don't see