山溪

bào fēng yǔ guò hòu shān xī biàn chéng le hóng liú

暴风雨过后，山溪变成了洪流。

After the storm, the mountain stream became a deluge.

gù guó bù yǐ shān xī zhī xiǎn

固国不以山溪之险。

It's not high mountains and deep valleys that best serve to defend a country.