1 sentence

1. 这条河谷由于长期的河流侵蚀而变得非常深。

   zhè tiáo hé​gǔ yóu​yú cháng​qī de hé​liú qīn​shí ér biàn de fēi​cháng shēn.

   This river valley has become very deep due to long-term river erosion.

   Source: Dong Chinese Dictionary