本章挑选了一些重要内容，希望带领读者快速浏览相关知识，作为本书的起点。如果读者对这一部分的知识已经相当熟悉，可以跳过本章直接阅读后面各章节的内容。-This chapter has selected some of the important contents in the hope to lead readers to quickly browse the relevant knowledge, as the starting point of the book. If this part of the reader is already quite familiar with the knowledge, you can skip this chapter directly read the contents of the subsequent chapters.