Looking at the endless clouds in the north, what does it mean to go to the water in Dajiangdong?

There is endless smoke in the north, and the water in the great river east is long: white clouds in the north, and the river flows eastward, never stopping.

PS: "There is no end to the cloud in the north, and the flowing water in the Dajiangdong River is long" comes from Huzhou Song written by Wang Yuanliang in the Southern Song Dynasty (VI): "There is no end to the cloud in the north, and the flowing water in the Dajiangdong River is long. The sunset is outside West Western jackdaw, and the southeast is 400 States. " This poem was written when the Yuan Dynasty destroyed the Song Dynasty, and the poet was escorting it. "Looking at the clouds in the north" means looking up at the north. White clouds are boundless, and there is no end in sight. This sentence actually refers to an unpredictable trip to the north. This difficult prison life seems endless, revealing the poet's anxiety about uncertain fate. "river of no return, for a long time" means that the rolling river flows eastward and never stops, and the poet's pain will never be cut off. Just like the long flowing water in the east, it shows the poet's deep and sad mood after his country broke and his family died.