Solution: as long as the gasoline in the tank is exhausted, the extra gasoline vapor in the tank can be fired into the cylinder by the negative pressure of the engine, and no gasoline vapor will overflow. In the 18th century, the western countries successively carried out the industrial revolution, the universal adoption of large machinery, laid the foundation for the establishment of factory system. In 1771, British man Richard arkwright1732-1792 founded the first cotton-yarn factory in the city of kron. In the 1930s and 1940s, the factory system was established in Britain, Germany and other countries. The main sex of factory system is: to carry out large-scale intensive labor; Using big machine to improve efficiency production; Implement the employment system; The division of labor is deepening and production is socialized. The establishment of factory system marks the real birth of enterprises. A report by the GMB union this summer warned that the number of workers who could be dismissed at short notice was nearer 10 million. Because economists understand earnings as actual material wealth increase, accounting experts think the output value of more than the difference between the input value is profits, there is a contradiction and two kinds of income concept. The specific performance is: Gasoline is the largest oil product consumed in the United States last year, according to the U.S. energy information administration (EIA). Last year, gasoline consumption averaged about 9.3 million barrels a day (391 million gallons) a day, a record high, about 47 percent of U.S. oil consumption.