Different depths. Undergraduate graduation thesis can put forward new theoretical viewpoints, explain existing theories from its own point of view, or even just an investigation report of a certain viewpoint; Postgraduate graduation thesis must have new contents, such as putting forward new theories, putting forward new viewpoints, new explanations and new arguments against existing theories. The arguments can be big or small, but they should be sufficient, rigorous, conclusive, accurate in calculation, rigorous in charts, innovative in the full text, and must not be copied, repeated or echoed.