A phrase is the smallest structure that constitutes an independent paragraph. The length of the passage depends on the tempo, tempo, and genre of the piece. The characteristics of a section are: 1. A section is the smallest structure in a musical work that expresses a complete musical idea or a relatively complete musical idea. It is the smallest complete musical form based on a single theme. 2. The components of a musical section are phrases, which are separated from each other by cadences, and are combined into an organic musical structure through the functional relationship of cadences. 3. A musical section is often composed of several phrases, and there is a question-and-answer relationship between these phrases. It is a common phenomenon to make up a section of two or four phrases, but there are also sections composed of three, five or more phrases, or a section composed of one independent phrase. 4. For passages in the main musical style, the way of expressing harmony plays a big role in stating, developing and ending the musical ideas. Therefore, the perfect ending of harmony and melody is a typical sign of the end of a musical section. A section can end in the key in which it started, or it can end in a relative key or a complete termination in another key, which is called a modulation section. 5. The structural scale of the section is generally not too large, but the form is complete and unified, and can reflect a distinct musical image. Since a passage is often the original statement of a theme, most passage statements are presentational. 6. A passage can be used as the form of an independent piece of music, or it can be part of a larger work. Sections that are independent works (especially instrumental pieces) generally have a more complex form than sections that are part of a piece of music. This is because in independent works, the passage not only has the statement, consolidation and ending of the theme, but also a certain degree of development, even a large-scale development. The above text is excerpted from "Music Works Analysis Tutorial" by Qian Renkang and Qian Yiping, Shanghai Music Publishing House, 2001, page 29.