Pre-defense is only a mock defense. Before the defense, the research group will make an internal defense. Warm up before you reply, and the teacher will help you improve. In order to do a good job in the defense of graduation thesis, the school, the defense Committee and the respondent (the author who wrote the graduation thesis) should make full preparations before the defense meeting.

As long as the preliminary defense is generally not a big problem, the external review is to prevent you from plagiarizing in a large space. As long as there is no such situation, it can generally pass.