学生选课系统：假定有n门课程，每门课程有课程编号，课程名称，课程性质，总学时，授课学时，实验或上机学时，学分，开课学期等信息，学生可按要求（如总学分

不得少于60）自由选课-Student Course Selection System: Assuming there are n courses, each course has course number, course name, course nature, the total hours, teaching hours, the experiment or machine hours, credits, semester course information, students may be requested (such as the total Credit shall not be less than 60) the free course