Introduction: Since Liu Chi got a book of "Elements and Array Basic Principles and Precautions", his life is like a dead end! It''s in the same vein: starting from the hot water bottle, then to the induction cooker, the balance car, the suspension car... all the way to the sword, the sword and the blood! Step on the world giants to climb up! When Liu Chi stood on the top of the world, looking back, the world had already been changed beyond recognition by himself. Science and business articles, don''t spray if you don''t like it. In order not to be eaten by mythical beasts, so... some content can be saved!...