Summarize the classification and main features of China folk music in about 800 words.

China national music is divided into: folk songs, folk song and dance music, folk instrumental music, folk rap music and folk opera music.

First of all, in terms of music composition, China music is based on pentatonic music. The so-called pentatonic mode is a mode composed of five tones: Gong, Shang, Jiao, Qian and Yu, which is similar to "1, 2, 3, 5 and 6" in the present notation. Six tones and seven tones in national music are developed on the basis of five tones. Secondly, in the form of musical expression, China's music pays attention to the horizontal development of music, that is, the expression of melody. Like China's calligraphy, painting and other arts, in terms of artistic style, China's music pays attention to the charm of melody, emphasizing the scattered form and the scattered spirit. Traditional China's music works are often performed in the form of a single melody, and harmony is rarely used. Thirdly, China traditional music is closely related to sister arts such as dance and poetry. In ancient times, music was generally inseparable from dance. For example, the six generations of music and dance in ancient times, the song and dance Daqu in the Tang Dynasty, and the opera music that appeared after the Tang and Song Dynasties all reflected the combination of music and dance. Ancient poems are generally divided into three categories: poems, words and songs. They were originally used for singing, but later the functions of poems were divided. From the perspective of modern music, most of the lyrics of songs rhyme, and a good lyric is also a good poem.