Off to one side, just below the crest of a little hill, there was a natural hideout.

在这条小径的一边，在一个小山顶的下面，有一个天然的隐蔽处。

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Tooth is a typical epithelium-mesenchyme organ, which is formed through the mutual function between the original oral epithelium and epiblastic mesenchyme from the neural crest below.

牙齿是典型的上皮-间充质器官，由原口腔上皮和其下方的神经嵴来源的外胚间充质相互作用而形成。

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As we walk over the crest, the bone-dry basin appears below.

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