The structural layer of a lyric (词的结构层) - what each section is for and what it must not say, which song form to pick, where the title lands and how often it comes back, and how line counts, line lengths and rhyme placement make a section feel finished or still owing something. Covers verse / pre-chorus / chorus / bridge / refrain functions, central versus developmental sections, AABA and verse-chorus and verse-refrain forms, the five structural parameters (balance, pace, flow, closure, closure type), the five hook-placement strategies, and the deliberate asymmetry that keeps a lyric from sounding machine-made. Use when laying out sections before writing a line, when a cho…