Due to the problems of high housing prices and high competition pressure in large first-tier cities, some young people who work and live in these cities in recent years have set off a wave of "escaping from Beijing, Shanghai and Guangzhou"-leaving large cities and returning to their hometowns Small and medium-sized cities seek development. However, the latest survey data shows that a large number of those who chose to "escape from Beijing, Shanghai and Guangzhou" originally chose to return to Beijing, Shanghai, Guangzhou and other large cities to re-search for work and life opportunities. If the following are true, which one does not explain the above phenomenon? ['Due to the impact of the country\'s "purchase restriction order", housing prices in some major cities have begun to loosen.', 'Most of the people returning from large cities to small and medium cities are not adapted to work and life.', 'It is often more difficult to overcome in large cities than in small and medium cities.', 'The infrastructure of large cities is more advantageous than that of small and medium cities.']