My best friend Betsy’s father was a manager at Hough Bakeries, which, at Easter time, made little bunny (兔子) cakes for all its stores throughout Cleveland. It happened that the plant downtown needed eight kids for temporary help during our spring break, for which I had no plans beyond listening to my favorite records. I’d earn minimum wage. I’d see how a factory worked. My parents thought all of this was a grand idea and called Betsy’s dad with their permission.

Our roles in the factory were simple: Place cakes on a moving belt. Attach icing (糖霜) ears. Apply icing eyes and nose. Remove bunny from the belt. This was harder than it sounds. Slow down a bit and the cakes pile up. As I told my parents at dinner that first night, it was all a little more high-pressure than I’d expected. 

这是2021新高考全国卷I完形填空中的一段。请问 bunny 是可数名词（查多本词典），为什么这里用了光杆名词？