Compare and discuss the similarities and differences between Han Yuefu folk songs and Southern and Northern Dynasties folk songs.

Yuefu folk songs are mainly composed of five-character poems, which are the main body of Yuefu in Han Dynasty, marking that narrative poems have entered a new and more mature stage of development. The representative is peacock flying southeast. At the end of Han Dynasty, Jian 'an poets represented by Cao Cao and his son appeared in Wei Chu, which set off the climax of literati poetry for the first time. Their poems are generous and sad, adopting a new five-character form. In the Southern Dynasties, most of them were love songs with puns. The language is fresh and natural, mostly short and pithy, and the highest achievement should be Song of the Western Zhou Dynasty. The folk songs of the Northern Dynasties are extensive in content, unpretentious in language and bold in style, and the highest achievement should be Mulan Poetry.