'Ball' exchange, 不雅，请慎入！

这是俺滴头儿讲的，已重复了N遍，仍乐此不疲。大意是：某叫兽突发奇想，要改造老龄老鼠，让它们再度焕发青春。此改造简单地说就是换“蛋”。"We take out young balls and put into an old mouse. The old becomes young. We take out old balls and put into a young mouse. The young becomes old."

于是，俺们动不动就听见“...... old balls becomes old, ...... young balls becomes young ......”。