某种鱼的鳞片有4种表现型：单列鳞、野生型鳞、无鳞和散鳞，由位于两对同源染色体上的两对等位基因决定(分别用Aa、Bb表示)，且BB对生物个体有致死作用。将无鳞鱼和纯合野生型鳞的鱼杂交，F₁有两种表现型，野生型鳞的鱼占50%，单列鳞鱼占50%；选取F₁中的单列鳞的鱼进行互交，其后代中有上述4种表现型，这4种表现型的比例为6：3：2：1，则F₁的亲本基因型组合是[ ]

A．aaBb×AAbb或aaBB×AAbb

B．AABb×aabb

C．aaBb×AAbb

D．AaBB×AAbb

— What do you feel about the concert held by Song Zuying in Bird's Nest?   

— Sorry, I have no idea. I ______ it because I happened to be on the plane that night.[ ]

A. missed          

B. had missed        

C. was missing      

D. would miss