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. In theoretical economics, investment means buying (and therefore producing) capital goods - not being consumed but being used in future production. Examples include building railroads, or factories, cleaning the land, or allowing yourself to go to college. Strictly speaking, investment in formula GDP= C + I + G + NX is also part of gross domestic product. In that respect, the function of investment is divided into non-residential investments (such as factories, machinery, etc.) and residential investment (new homes). The correlation between I = (Y, I) is known to have a close relationship with income and interest rates. Higher incomes would boost higher investment, but higher interest rates would discourage investment because it would be more expensive to borrow. Even if companies choose to use their own funds to invest, interest rates represent the opportunity cost of investing in those funds rather than the interest that will lend out. The investment quantity is the decreasing function of interest rate, saving is the increment function of interest rate, and the change of interest rate depends on the equilibrium point of investment quantity and saving amount. Keynes's theory of money supply and demand decided that interest rates were a monetary factor rather than an actual factor. The fund's managing director Christine Lagarde said Christine Lagarde, in June 2016, voted to leave the European Union has an impact, the British economic growth this year and in other parts of the world economic growth.