108 years ago today, on October 15, 1917 (August 30, 1917 in the lunar calendar), Peking University began to implement the elective system. On October 15, 1917, Peking University convened a meeting and decided to proceed with the reform of the academic system. According to the American university academic system, the elective system was adopted. The specific measures stipulate seven items: 1. Each subject has a systematic preparation. 2. Students graduate with a number of units completed, and there is no need to set a time limit. 3. Forty units of preparatory courses, with three-quarters as compulsory subjects and one-quarter as elective subjects. The selection of subjects is designated by the director of each preparatory course according to their level. 4. Eighty units of undergraduate courses, half as compulsory subjects and half as elective subjects. 5. When undergraduate students enter the school, they must choose an undergraduate professor as a tutor. Sixth, the selection of subjects is not limited to the department of the discipline, but also has an important relationship with the specialty, and the scholars who are willing to treat other scholars also listen to it. Seventh, where the average score of the previous academic year is in the first grade, the most units specified in the selection of subjects can be selected this academic year. This is the beginning of the selection system in our country's universities.