In 1934, professor rei, of the center for fluid mechanics, used model cars to measure the aerodynamic drag of various bodies in wind tunnels 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: The API data also showed that us crude imports last week fell by 138,000 barrels/solstice7100,000 BPD. We should improve the market supervision system of administrative law enforcement, industry self-discipline, public opinion supervision and mass participation.