What do you mean by three and a half sentences?

"Three sentences and a half" is a traditional folk art performance form in China. It is named because a group of expressive words consists of three sentences and a phrase. Usually four people perform. The first three people each recite a lyric, and the fourth person recites a phrase or word that summarizes the first three sentences, that is, one and a half sentences. The last sentence should make the audience feel fresh at this moment. And so on until the end of the performance. Performers need to hold percussion instruments such as gongs and drums when performing, and each sentence will be struck, adding rhythm and contrast atmosphere to the performance. Four sentences in a round, about eight to ten rounds.