蝙蝠有一个问题：该如何在黑暗中找到他们的道路。

Bats have a problem: how to find their way around the dark.

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但是，有一个令人苦恼的问题是：为什么蝙蝠是唯一的比人类具有更好听力能力的哺乳动物？

The vexing question is: Why? Bats are the only mammal with a better ability to hear changes in pitch than humans do.

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