According to the score of 15, it belongs to level 5. Basically to the point, but there are many mistakes, and the expression is not in place. In addition, the example of "elective" you gave is not appropriate, such as mathematics and biology, which are definitely compulsory courses rather than elective courses. In addition, if you are preparing for CET-4, you don't need to prepare this article. You passed the exam in 2007. I found an article written by others for your reference.

With the reform of higher education in China, more and more colleges and universities attach importance to the cultivation of students' ability. Therefore, elective courses are not only suitable for excellent students, but also suitable for middle-level students.

Of course, students choose their own elective courses for different reasons. For some people, practical skills are the essence of university education, so computer science, marketing and finance courses are their first choice. On the other hand, others may hold the idea of free education, and elective courses on literature, history and philosophy are the most popular.

Take myself as an example: as a believer in liberal education, I support the view that universities are not places to learn survival skills, but halls of knowledge and critical reasoning. Although my major is chemistry, my most elective courses are English literature, introduction to classical music and different schools of western painting. They really broadened my horizons.