According to the length, there are mini passenger cars (no more than 3.5 meters), small passenger cars (3.5-7 meters), medium-sized buses (7-10 meters) and large passenger cars (more than 10 meters). In 1937, American economist Robert coase (R. H. Coase's publication of the essence of the enterprise is considered to be the beginning of a discussion on this issue. What happens next? Opportunities in 2018