English classes in Tsinghua are divided into Grade One, Grade Two, Grade Three and Grade Four, so the scores of graded examinations are Grade One, Grade Two, Grade Three and Grade Four. Grades one to four are getting better and better.
Students who are assigned to Grade One and Grade Two need to take corresponding English classes in Grade One and Grade Two, and freshman is a compulsory course.
If you are assigned to Grade 3 or Grade 4, you can take English classes (optional). Tsinghua's English class is in a marginal position, so I can probably understand it after coming.
It is suggested that students who are assigned to grade three or grade four take the CET-4 exam in the freshman semester and take the CET-1 exam in the freshman semester. Because first of all, these exams are beyond the ability of students who have completed the college entrance examination. Secondly, seniors will tell you that since you came to Tsinghua, your English level has been declining year by year, which is true.