Grinding and cutting
Molongqie, a Chinese idiom, Pinyin is m ó L ó ngju ā nqi, which means sharpening and exchanging. It comes from Jin Shuo by Wang Anshi of Song Dynasty.
The origin of Idioms
Wang Anshi's Jin Shuo in the Song Dynasty said, "grind the surface and cut it, immerse it in irrigation and nourishment, and prepare it after the line is finished."
Idiom explanation
It means to sharpen and learn from each other.
Grinding and cutting
The ground is a golden stone - zhì dì zuò jīn shí shēng
The letter covers the whole world - hán gài qián kūn
Love the new and forget the old - liàn xīn wàng jiù