Daya and HowNet are two completely different duplicate checking softwares, and the test results can't be used as reference. When selecting the duplicate checking system, it should be selected according to the requirements of the school to ensure the accuracy and reference significance of the duplicate checking results. For the first draft of the paper, it is suggested that free duplicate checking software such as paperfree, papertime and paperday can be used. And for the final draft, use the duplicate checking system required by the school to ensure that the paper meets the requirements of academic norms.