Reduplication refers to a method of expressing emotion by repeatedly singing the upper and lower sentences or the upper and lower paragraphs with the same structure. This is a common skill in poetry. This technique has the effect of repeated expression and the beauty of phonology, artistic conception and implication.
On the content and theme: deepen the artistic conception, render the atmosphere, strengthen the feelings and highlight the theme.
In the expressive force of poetry, it enhances the sense of rhythm and music of poetry, forms a kind of recurring beauty, and gives people a euphemistic and lasting charm.