1, the first level: the possible problems were not fully considered in the conceptual stage before writing.

2. The second level: I don't know what to do about some problems that have appeared in the writing stage.

3. I don't know what to change and how to change it in the revision stage after writing. Zhengzhou University, referred to as "Zheng Da", is located in Zhengzhou City, Henan Province. It is a university jointly established by the Ministry of Education and the People's Government of Henan Province. It is a national "double first-class" construction university, "2 1 1 project".