Kailov. The Union of Soviet Socialist Republics, referred to as "Soviet Union" for short, is a federal socialist country, which existed in 1922- 199 1 year. It is ruled by the Soviet Union and consists of 15 republics with equal rights according to the principle of voluntary association. In the former Soviet Union, Kailov made a valuable contribution to the history of pedagogy science, and his pedagogy also had a very important influence on China, which was the most widely spread. The Soviet Union played an important role on the world stage in the 20th century. In the field of science and technology, the Soviet Union keeps pace with the United States in aerospace, and a large number of scientific and technological forces and achievements are concentrated in cutting-edge departments such as nuclear weapons, missiles, atomic energy and space technology.