The main song is a relatively dull part in the beginning or middle of a song. Generally, even if it is repeated, most of them will change the lyrics.
The chorus is the center, which is the climax and essence of the song. Generally, it will be repeated, and the lyrics are rarely changed. Even if it is changed, it is also an individual sentence. In order to emphasize the meaning, from the emotional point of view of the tune, the main song is often narrative and the chorus is often expressive.
Detailed comments
The structure of general popular songs consists of main song (verse) (a), chorus (b), transition sentence (parenthesis) (c), popular sentence (memory point) (d), instrumental music and ending (prologue, passage and interlude) (e). Generally speaking, the main song can be said to be the content and backbone of every music. The structure of music has a special type, which is called musical form in music theory.