How does a poem become a sentence?

There were no punctuation marks in ancient times, and scholars had to break sentences by themselves, which is one of the reasons for the ambiguity of many ancient books. The punctuation used now was introduced from the west after the New Culture Movement. Today, in order to read ancient books conveniently, they punctuate them according to their meaning. Most of the ancient poems are mainly rhythmic, with chapters and sentences, which are easy to break. Modern poetry uses lines to break sentences.