鸭子被吃掉了

来源: 于 2010-05-14 09:26:39 [旧帖] [给我悄悄话] 本文已被阅读：次

Yes, I know what you mean.

1:x = Vf: Vduck
PI: 1-x = Vf : Vduck

so the fox (or cat) will be there to eat this duck.