The paper was already written when the topic was answered. According to the relevant information, you need to submit a paper to open the topic. Without the foundation of the thesis, the defense teacher can't judge your academic research, and it is difficult to ask meaningful questions. As a student, you should hand in your thesis to the defense teacher in advance and answer questions according to it during the defense. The opening defense is divided into two parts: opening report and defense. In fact, it is a form of comprehensive review of the results of the initial and planning stages of the project by relevant personnel.