Personal opinions and interests are the most important, and only by enjoying them can we learn knowledge from complicated historical materials. As for the difficulty, it should be to overcome anxiety. The purpose of studying history is to learn from experience, not to remember events that have happened. People nowadays are often reluctant to look up piles of data bit by bit. They prefer to have a database-like system to help them get what they want instantly, but the fun of history can only be explored from the mountains of historical materials, which is the most difficult in this impetuous real society.