In fact, it is the ability of reasoning and analysis. A seemingly complex problem is often synthesized by simple problems. In the process of reasoning and analysis, starting from small problems, complex problems are decomposed into single problems, just like computer programs, realizing modularity and realizing a function in one module. The outlet and inlet of the connection between modules are fixed. When a question needs to call the analysis result of another question, it only cares about what the result is.