time flies
The Chinese idiom Li ú Gu āì ngy ì sh ì in pinyin means that time flies very fast. It's from near the sand.
The origin of Idioms
Song Qi's "waves wash sand near" says: "young people don't care, the flow of light is like an arrow, because they follow, they don't feel the change of time."
Idiom usage
Used as an object or attribute; used of time, etc. example success is rare and fleeting. (Chapter 46 of the popular romance of the Republic of China by Cai Dongfan and Xu Xianfu)
time flies
particular things improve with the improvement of the general situation - shuǐ zhǎng chuán gāo
A stalemate between clam and snipe - bàng yù xiāng chí