A: Different countries have different school education systems in different historical periods. Nowadays, modern schools in the world have formed a complex system. The modern school system consists of three structures, one is the dual-track school system, represented by western European countries, and the other is the single-track school system, represented by the United States. The educational structure between the above two educational systems is intermediate, also known as the subject-based education system, represented by the former Soviet Union. (1) Dual-track school system In Western Europe in the 18 and 19 centuries, under the influence of social, political and economic development and specific cultural and historical conditions, academic modern schools with traces of hierarchical privileges and new mass modern schools for working people's children also developed relatively comprehensively, thus forming a dual-track school system for modern education in Europe. A top-down track, its structure is university and middle school; The other track is bottom-up, and its structure is primary school, followed by vocational school. These two tracks are neither connected nor interlinked, thus depriving the children of working people studying in ethnic schools of their right to enter middle schools and universities. Later, the national education school developed from primary school to middle school, and there was a corresponding junior high school part. (2) Monorail school system Monorail school system was first produced in the United States. Most parts of North America initially adopted the dual-track school system. Harvard and Yale are copies of Oxford and Cambridge, while Latin schools are copies of grammar schools. Later, Shi Wen Middle School replaced Latin School as the main institution of secondary education. In the19th century, due to the industrial revolution and the tradition that the United States has no privilege, the original academic track of the American academic system has not been fully developed, but it has been submerged by the mass primary and secondary schools that have developed in a short time, forming the American monorail academic system. The structure of the monorail school system in the United States is: primary school, middle school, and then college. The American education system is characterized by a series and multiple parts. (3) The school system in Tsarist Russia is also a dual-track school system. After the October Revolution, the former Soviet Union established a single-track socialist unified labor school. Later, in the process of development, some traditions of the original liberal arts middle schools and the practice of setting up vocational schools separately were restored, thus forming a Soviet-style academic system with the characteristics of single-track system and dual-track system. This kind of education system is different from the dual-track education system in Europe, because it is not divided into tracks at first, and graduates from vocational schools also have the right to enter counterpart institutions of higher learning. But it is different from the American monorail school system, because it began to branch in the middle school stage, which is the branch school system of the former Soviet Union.