First of all, there is no literature review in the opening defense. Specifically, the normal order is that, generally speaking, before opening a defense, you need to write an opening report, and after the defense, you can write the text. The literature review here is generally after the text, so there is no literature review in the opening defense.

Requirements for literature review:

It requires the author not only to comprehensively sort out and state the main points of the materials he has consulted, but also to make a more professional, comprehensive, in-depth and systematic discussion and corresponding evaluation of the comprehensively sorted documents according to his own understanding and understanding, rather than just "piling up" academic research in related fields.

Literature review is a style different from research papers, which is composed of understanding, sorting, comprehensive analysis and evaluation after researchers read the literature on a certain topic in advance.