《搜神记·卷十二》
当牛哀是人的时候，他并不知道自己将要变成老虎；当他成为老虎的时候，也不知道自己曾经是人。
其兄启户而入，搏而食之。方其为人，不知其将为虎也；方有为虎，不知其常为人也。
When Niu Ai was a human, he didn't know that he would turn into a tiger; when he became a tiger, he didn't know that he had once been human.
<s>[INST] Translate the following passage from Classical Chinese to both modern Chinese and English, focusing on preserving the emotional tone in both translations: 其兄启户而入，搏而食之。方其为人，不知其将为虎也；方有为虎，不知其常为人也。 [/INST] Modern Chinese: 当牛哀是人的时候，他并不知道自己将要变成老虎；当他成为老虎的时候，也不知道自己曾经是人。 English: When Niu Ai was a human, he didn't know that he would turn into a tiger; when he became a tiger, he didn't know that he had once been human.</s>
Translate the following passage from Classical Chinese to both modern Chinese and English, focusing on preserving the emotional tone in both translations: 其兄启户而入，搏而食之。方其为人，不知其将为虎也；方有为虎，不知其常为人也。
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Modern Chinese: 当牛哀是人的时候，他并不知道自己将要变成老虎；当他成为老虎的时候，也不知道自己曾经是人。 English: When Niu Ai was a human, he didn't know that he would turn into a tiger; when he became a tiger, he didn't know that he had once been human.
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