The tutor can instruct the undergraduate graduation thesis to write the year when the thesis is published. According to the relevant information of the query, the number of years of the paper refers to the number of years that the whole paper has been used in document retrieval, that is, the year when the paper was published. That is to say, writing this paper by myself is a process of inquiring and learning from other places, which has certain historical significance. Therefore, in order to achieve authenticity, the number of years in the data is not allowed to be modified. The number of cases refers to the total number of cases used in the paper.