It is legal, after all, it needs invigilation and marking. All this requires manpower, and of course money.

1902 before the reform of the education system, although China's middle school education had a certain development, its internal administration was still very chaotic, and the establishment of administrative organizations was mostly based on the subjective opinions of school operators, which had no scientific basis, which also had a certain adverse impact on the healthy development of middle school education in China. Moreover, because the academic system was not established at that time, the national school management was in a disorderly state, and people urgently needed a comprehensive reform of education. Under the pressure of people's demands and the rapid change of social situation, the Qing government began an attempt at educational reform in 1902, and issued the Charter of Britain and Wang Xuetang, which stipulated that middle schools should be called "provincial middle schools" and "private middle schools" based on the principle of government establishment. To this end, China has a special way to set up secondary education, stipulating that the "prime minister" is "the person in charge of school affairs in an all-round way", that is, the prime minister is the principal. Unfortunately, the Charter has not been implemented. After graduating from junior high school, I usually take the senior high school entrance examination (junior high school level examination). The content of the senior high school entrance examination generally includes 10 basic subjects (Chinese, mathematics, foreign languages, physics, chemistry, biology, politics, ideology and morality, history, geography and physical education). Among them, the biology and geography exams are conducted in the second semester of the second grade, and the third grade is not reviewed.