A person who really understands music can appreciate music by himself and know where the music is really good. He doesn't necessarily feel that the melody is beautiful, so this song is good. It is to really understand the background of this music, understand what instrument he plays, or analyze the lines of melody and the direction of harmony. Strong and weak changes, and then why do you compare the strong and weak changes in this place ... Moreover, people who know music are generally very high in artistic accomplishment, not to say that they can listen to music, but to sing music means they know music. Music is actually very difficult to learn, and it is very important to have an innate feeling for music, and the efforts made the day after tomorrow are also very important.