Poetry is expressed in language. He has two conditions, one is the way of expression and the other is the subject of expression. The way is restricted by many forms, such as meter, artistic conception and many other related skills; The other is the subject, that is, the content. Modern poetry pays more attention to the way and ignores the subject. Theme-refers to the poet's outlook on life, values and feelings about life. Therefore, people in the liberation period are simple and sincere, which is lacking in contemporary times.
I hope it helps you.