Some would say that the central bank's way of ensuring independence is to abandon macroprudential policies and micro-prudential policies and to take unconventional interventions in the securities market. But the crisis is an important lesson, macroeconomic and financial policies are closely connected, when the two tasks in the same institution, management by different commission, their coordination is the most effective. And because interest rates are low and uncertain, a crisis is coming, and unconventional policies will come back. Investment in securities provides an important channel for the society to raise funds, which is an effective way for enterprises to raise direct financing. Investment in securities is conducive to adjusting capital investment and improving the efficiency of capital use, thus guiding the rational flow of resources and realizing optimal allocation of resources. The rubber hose in the engine compartment will be used for a long time and it will be a problem for older vehicles. Once aging, gasoline can leak into the engine compartment. The air conditioning system will allow the smell of petrol to enter the car. Therefore, once the rubber tube is old, need to change promptly!