What is the name of the recurring lyrics in the poem Song of the Yangtze River, and what is the function of this writing?

This kind of writing is called repetition, which is used to express the author's attachment and praise to the Yangtze River.

Advantages of repetition: repetition has the rhetorical effect of highlighting thoughts, emphasizing feelings, distinguishing levels and strengthening rhythm. Therefore, it is used in various styles to strengthen the arguments in reasoning articles; In narration, coherence can be distinguished; Repetition in literary works, especially poetry, can express strong and profound thoughts and feelings, emphasize the theme and enhance the beauty of melody.