Opera can be divided into two categories: serious opera and popular opera according to its nature.
Serious opera, including the 18th century formal opera in the West, the grand opera of the 19th century, the opera of the serious opera genre of the 20th century, and some operas in the East. Its characteristics are roughly as follows: first, there is a more rigorous and complete first-class drama structure; second, there is a more distinct image and its development; Third, the plot is often a major theme, a historical event, or a reflection of social and philosophical issues. His representative works are: Ober's "The Dumb Girl of Portici" and Rossini's "Wilhelm Dyer".
Popular operas include comic operas in the 18th century, operettas in the 19th century, and ** operas in the 20th century. Its characteristics are roughly as follows: first, it is easy to understand, beautiful and easy to accept; secondly, each piece in the play has a certain degree of independence, without necessarily emphasizing the development of the drama and the integrity of the dramatic structure (not emphasizing does not mean that there is none); Third, in terms of plot, there is often irony and humor, but it is not necessarily true; Fourth, there are often confessions in the play, and it is a confession that has completely stopped, and even the development of the plot completely depends on the confession (of course, there are also those who are not said in the whole play); Fifth, it is often a combination of singing, speaking, dancing, acting and band playing. Her representative works are: "La Traviata" and "Phantom of the Opera".