6. The accounting benefit is bound by the prudent principle. According to the principle of prudence, when there are a variety of accounting methods to choose from an economic business of an enterprise, it should choose a method that neither overestimates nor depreciates the benefits. Enterprises manipulate profits to achieve homogenization of profits, most of which adopt the method of overestimating earnings, and the subjective selection of the period of value-added. There were two opposing views of development in the 19th century. A push performance degradation is based on the second law of thermodynamics system, it argues that, due to the dissipation of energy, the world tends to be weak, the universe tends to "heat death", the structure of the retreat, disorder tend to the maximum, the whole world over time and the process of dying; Another is based on Darwin's theory of evolution of the evolution of the concept system, it points out that social evolution is the result of the increasing division of species, the evolution and increased, structure complex and orderly, and constantly reinforced by functional evolution, all nature and human society are to develop more advanced, more orderly organization structure. Modern economy, the interest rate as the price of money, not only restricted by many factors in the economic and social, and changes in interest rates to have a great impact on the economy as a whole, as a result, modern economists are studying the interest rate decision problem, pay special attention to the relationship between the variables and the balance of the economy as a whole, the interest rate decision theory has experienced the classical interest rate theory, Keynes's interest theory, interest rate in loanable funds theory and is-lm analysis as well as the contemporary evolution of dynamic interest rate model, the development process.