北京山区水土流失严重，山洪、泥石流灾害时有发生。

There are serious soil erosion problems in Beijing mountain area, where floods and debris floods happen frequently .

youdao

北京山区水土流失严重，山洪、泥石流灾害时有发生。

There are serious soil erosion problems in Beijing mountain area, where floods and debris floods happen frequently .

youdao