What is the content of this poem about the Han River?

Dissolved and dissolved, Bai Ou flew, green and clean, and it was good to dye clothes in the deep spring; People who travel from the south to the north are old, and the sunset is long to send fishing boats home. -Du Mu's poem "Han River" was written by the poet Du Mu when he walked through the Han River on an evening in late spring. In the first sentence of this poem, the poet wrote on the surface of Hanshui River. The water waves are swaying, and a group of Bai Ou are dancing on the water, full of movement in a quiet environment. In the second sentence, the poet focuses on the "green" of the river, which is green enough to dye clothes; This idea is novel and ingenious. The word "late spring" simply points out that the author crossed the Han River in late spring. In the third sentence, the poet thinks of pedestrians coming from south to north in front of him, running around and wandering around, and unconsciously becoming the boss! "The last sentence, Syria wrote the poet looked at the sunset fishing boats on the river, far home, and he has not been able to go home. The whole poem is full of faint sadness and emotion.