答案：
Because the rabbit thinks the pig is dirty and the cow thinks the pig is dirty and smells bad.
本题翻译：
为什么兔子和奶牛不想和猪一起玩?
根据文章中兔子和奶牛对他说的话：
You're dirty. I don't want to play with you. You should brush your teeth every day. Look at my teeth. They're white and clean.
你很脏。我不想和你玩。你应该每天刷牙。看看我的牙齿。它们又白又干净。
You're dirty and you smell bad. I don't want to play with you. You should take a bath every day.
你又脏又臭。我不想和你一起玩。你应该每天洗澡。
本题答案可总结为：Because the rabbit thinks the pig is dirty and the cow thinks the pig is dirty and smells bad.
