Generally, a doctoral thesis can be submitted for review at most twice. Generally, doctoral dissertations need blind evaluation, and five experts are usually sent. Experts have three levels of evaluation, namely, excellent, qualified and unqualified. If the first submission is all qualified or excellent, there is no need to submit it again. If any evaluation expert fails, they need to find another expert to evaluate. If they are qualified, they can reply. If you fail, you can only wait for the next time.