little question

I have some questions and I want to interrupt you. Don't rush to read it, and don't have to answer it right away, that is, I have some thoughts, and I want to borrow your place to write. This is a very abstract question, and it is difficult for me to describe it in one or two sentences. The reason is this, after watching the movie 1921, I found a very interesting place, that is, the historical figures directly said the lines in the history textbook. For example, before the convening of the National Congress of the Communist Party of China, Li Da uttered the idiom "opening up the world". This situation is very obvious early in the film. So I thought, as we have memorized it for so long, where do these peculiar statements about history come from in modern history. Like this "early ground, a new look, fired the first shot of armed resistance to the Kuomintang reactionary rule, etc." Where did these unique historical descriptions come from, and how were they written into our history textbooks. I don't even know how to google such a question. At present, with my common sense, I feel that the Selected Works of Mao Zedong, the resolutions on some historical issues of the Party since the founding of the People's Republic of China, and Fan Wenlan's modern Chinese history may be the main sources.