What is the meaning of "Once the river is clear, how long will we live"?

Once the river is clear, the meaning of "Once the river is clear, how long will people live" is that people's life span is very short and waiting for the Yellow River to become clear is impossible. The metaphor is that what is expected cannot be realized.

Once the river is clear, the geometry of human life is an idiom meaning that human life is very short and waiting for the Yellow River to become clear is impossible. It is a metaphor for the failure to realize what is expected. Source "Zuo Zhuan - Xiang Gong 8 Years": "Zhou Shi" has this to say: Once the river is clear, how long will people live?

Zuo Zhuan (左传), which was written by Zuo Qiu Ming (左丘明) during the Spring and Autumn Period and is believed to have been compiled by someone in the Warring States period, is the first chronicle of ancient China with a complete narrative, and it is also a representative of the prose works of the pre-Qin dynasties. The original name of the work was Zuo's Spring and Autumn Annals, and it was renamed as Spring and Autumn Zuo's Biography, Spring and Autumn Inner Biography, Zuo's, and after the Han Dynasty, it was mostly called Zuo Zhuan.

It is one of the important classics of Confucianism, and it is an important study history book for Confucian scholars of all generations, and it is called "Three Chuan of Spring and Autumn" together with "Gongyang Chuan" and "Gu Liang Chuan". Zuo Zhuan is essentially an independently written work of historical literature, which began in the year of Lu Yin Gong Yuan and ended in the 27th year of Lu Ai Gong, with the Spring and Autumn Annals as the basis for the program of the Spring and Autumn Annals through the description of specific historical facts of the Spring and Autumn Annals period.

Zuo Zhuan, one of the 100 Classics of Chinese Excellent Traditional Culture, has been released in 2021. Zuo Zhuan is rumored to have been written by Zuo Qiu Ming, a historian at the end of the Spring and Autumn Period. Sima Qian, Ban Gu and others believed that Zuo Zhuan was written by Zuo Qiu Ming. The Zuo Zhuan is based on the Spring and Autumn Annals and illustrates the outline of the Spring and Autumn Annals by recounting specific historical facts of the Spring and Autumn period.

Evaluation of Zuo Zhuan:

Zuo Zhuan represents the highest achievement of pre-Qin historiography, and is an important document for the study of pre-Qin and Spring and Autumn period history, which had a great influence on the historiography of the later generations, and in particular played a great role in the establishment of the status of the chronological history books.

And because of its strong Confucian tendency, emphasizing the hierarchical order and patriarchal ethics, and valuing the difference between the eldest and the youngest, as well as showing the idea of "people-oriented", it is also an important historical material for the study of pre-Qin and Confucianism.

Zuo Zhuan is not only a historical work, but also a very good literary work. It is characterized by a long history of war, which is called the "Book of the Chopper", a good characterization, and an emphasis on the recording of rhetoric.