How does Up the Hill and Down the Beam use the two-language structure that echoes up and down?

The "uphill and lower beam" of Xintianyou in northern Shaanxi is also a two-stage structure that echoes up and down. The whole song adopts the seven-tone quotient scale, and the melody is ups and downs, and the melody is richer. The first sentence starts from re (tonic) in the high-pitched area and goes up to sol, the highest note of the whole song, and then the fourth and seventh intervals are used in succession, and the octave jumps up and down, resulting in the fluctuation of the melody. The last sentence extends on the pentatonic la above the tonic to form a paragraph. After the alto is slightly extended, the next sentence gradually drops to the bass area and finally ends in the tonic. The whole song is not only rigorous and symmetrical in structure, but also tortuous and changeable. The long breath and slow rhythm make the music rich in loess plateau style, desolate, broad and charming.