In his theory, money supply is controlled by the central bank and is an exogenous variable with no interest rate elasticity. At this point, monetary demand depends on people's psychological "liquidity preference". I've been trying to get a refund because I collected more money and was turned down. It claims that I have been charged with the "cheapest" fare, although it admits that the price of the app is not correct. The accounting income follows the historical cost principle and the matching principle, which is conducive to the objective reflection of the business management responsibility of the enterprise management authorities. But, due to the historical cost principle inherent defects, especially according to the present value of revenue and expenses by historical cost line, makes the calculation of accounting earnings lack of inner logical unity, and the matching principle is difficult to carry out, so that the book value of assets can not reflect its real value, cost cannot be fully compensated. And the economic benefit is measured in the current value, which reflects the actual value of the asset, which is beneficial to the full compensation of the cost. Point five: look at the repayment risk. Reimbursement risk fee, is that when investors corresponding borrower overdue list creditor's rights or bad debts, so risk fee reimbursement amount of account can be used to repay the principal and interest first, this will let next fall risk level, safety coefficient is relatively high, so it is more important, investors when the choice must be made sure.