The expression technique refers to the overall technique of poetry. The expression techniques in the "Book of Songs" are generally considered to be three types: "Fu, Bi, and Xing". This is most obvious in the "Book of Songs" , and was widely used by later generations of poetry. And what you call "repeated chapters and repeated chants" can be said to be a characteristic of poetry, and it is also widely reflected in many poems in the "Book of Songs". As far as I know, it is not strictly defined as The expression techniques of "The Book of Songs" are generally considered to be the characteristics of "The Book of Songs".