profit maximization problems It doesn't seem to be too much of a market to really focus on learning or learning about the importance of learning. More and more, I feel that learning is to keep to the only way to do it for a long time in the market, continuous learning can bring something new to you constantly, in a sense, the ability of learning will be able to represent your trading ability and analysis ability. Then the interest rate theory of the loan is the interest rate theory of neoclassical school, which is proposed to correct Keynes's theory of "liquidity preference". In some ways, the theory of interest rate can be regarded as a synthesis of classical interest rate theory and Keynesian theory. With the development of social division of labor and market economy, the concept of market is also developing and deepening, and the multiple meanings of different levels are reflected in the deepening of the project. Finally, the regulatory layer began to conduct financial management of the Internet platform, intending to return money funds to the source of low risk, low yield and high liquidity. Leakage may occur at the interface of the gasoline pipe, which leads to the use of the air conditioning system into the vehicle. If the owner found the car fumes, deal with gasoline pipeline - open interface to check engine hatch, it is easy to discern does the interface of gas leakage, for a period of time after the leakage surface will appear a layer of oil sludge. If the leakage of the gasoline pipe is found, the interface should be tightened or repaired.