Grade 20 18 refers to the class of grade 2022. Graduates are generally called grades, not grades. Grade is the year when students enter school. For example, grade 20 18 means that they entered school in 20 18 and are in school. The first year is the graduation year of school students. For example, students in grade 20 18 graduated in 2022, so they became the class of 2022. On the other hand, "grade" focuses on welcoming new students and distinguishing the grades of students in school, while "grade" focuses on seeing off graduates and alumni who have participated in social work.