At the beginning of the article, the source of the title is explained, which means that although the title comes from two sentences in the ancient books "Book of Rites" and "Laozi", it is different from the original intention and is taken out of context. This explanation can not only prevent the listener from confusing the topic with the wishes of the sentences in the Book of Rites and Laozi, but also show the scientific nature of the discussion and the interest of the speech. At the same time, the reason of the topic is put forward, which is also convenient to reveal the main points of the whole article and make the listener have a general understanding of the outline of the speech.