What do you mean by four words and seven sentences?

Four-character style refers to a poem composed entirely or mainly of four sentences. Seven-character quatrains are a kind of quatrains, which belong to the category of modern poetry. The quatrains are composed of four sentences, which have strict metrical requirements. Common quatrains include five-character quatrains, seven-character quatrains and rare six-character quatrains, each of which is seven words.