As an experienced person, I know this well. Of course, there is one mode that is the most difficult. It makes you find many shortcomings. You can use it to understand your own strengths and weaknesses, and then make more effective ways to learn. The second mode is simple, and the third mode is simple. Because you have mastered many shortcomings, the teacher will make the questions simpler in order to give everyone confidence. The above is for reference only, I hope it will help you.