public profit Gasoline sales in the United States are mainly due to competitive gasoline prices and rising fuel efficiency, with a high seasonal impact. Population and cultural factors are also important factors that influence the trend of gasoline consumption in the United States, according to Jill Mislinski, an analyst with Advisor Perspectives. Adam Smith began as a logical starting point for "the personal gratification of the activity of personal gratification," and the market was "laissez-faire". The activities of the government completely unable to intervene in the pursuit of personal wealth, also don't have to worry about the laissez-faire altogether will create chaos, "an invisible hand" will be taking the laissez-faire personal economic activities arranged in perfect order. In other words, Adam Smith's market concept focuses on limiting government interference in individual economic activities. The wealth of nations also spends a considerable amount of time attacking the mercantilist policies that interfere with individual economic activity and limit individual economic power (property rights). Later classical economists stuck to their laissez-faire views. I've been trying to get a refund because I collected more money and was turned down. It claims that I have been charged with the "cheapest" fare, although it admits that the price of the app is not correct. In addition, the national standard has strict regulations on the content of various chemical components of gasoline such as benzene and olefins. Alkenes are high in content, which can produce gelatinous substances in the process, and accumulate in intake manifold and valve catheter. When the engine is in normal working temperature, there is no abnormal phenomenon; When the engine has cooled for some time, the glial will stick the valve inside the valve tube. When you start the engine, you will have a top valve phenomenon. The toxic benzene content should not exceed 1%.