in a cost volume profit chart the In order to overcome the rear overreach of the ship's car, a strong air eddy effect was created when the car was traveling at high speed, and people developed fish shaped cars like the back of a fish. In 1952, general motors' buick sedan ushered in the era of fish cars. In terms of the shape of the car's back, a fish-type car is similar to a beetle. But as observed carefully, will find fish type car back and ground into the Angle is small, the tail is longer, around the body of the air flow is relatively easier, so vortex flow resistance is also relatively small. Wedge car “Our entry for this award is a thank you to them for their vision and willingness to do things differently. It’s also a thank you to BEIS for the courage and far-sightedness they have shown in working constructively with industry to fit their approach to the needs and circumstances of UK manufacturing.” The market is the economic contact method which is the basic content of Commodity Exchange. Under the condition of commodity economy, the premise of exchange generation and existence is social division of labor and commodity production. Because of the social division of labor, the different producers, respectively, engaged in the production of different products, did not meet the needs of themselves and others and exchange their respective product, so that the general labor products into commodities, make the product production is transformed into commodity production. It is under this condition that the market for goods to be exchanged to meet the needs of different producers is born. Therefore, the market is the product of the division of labor and the exchange of goods under the conditions of commodity economy. The market and commodity economy have inalienable internal relation. According to this model, the interest rate decision depends on the supply of savings and investment needs, money supply, money demand, four factors, cause a change in the saving investment, money supply and demand factors will affect the level of interest rates. This theory is characterized by general equilibrium analysis.