Economist lynde hull explained that the benefits of capital in different periods of time would be interest. According to linde hull, interest in a specific period and the difference between the expected consumption is savings (during the period of the growth of capital), and returns the sum of consumption and savings are given period of time. Moment of torque There is no ambiguity in the objective of the concrete plan. For example, business sales managers intend to increase sales by 15 percent over the next six months, and he will formulate specific procedures, budget plans, and schedule schedules, which is the concrete plan. Guideline plans only some general guidelines and action principle, favors the actors free disposition, it points out that the key but don't limit actors on the specific target or specific action plan. For example, a specific plan to increase sales may require a 15 per cent increase in sales over the next six months, while a guidance plan may limit sales by 12 to 16 per cent over the next six months. Compared with the guidance plan, the concrete plan is easier to carry out, assess and control, but lacks the flexibility, and its requirements for clarity and predictability are often difficult to satisfy. In the 1920s and 1930s, the great depression forced western economic theorists to reflect on the definition of the market. The final answer is completely laissez faire is not enough, the invisible hand sometimes does not exist, market failure, government should be on economic activity on the "total" intervention, so "macroeconomics" was born. Roosevelt also accepted Keynes's proposal to impose a "New Deal" on government intervention in the economy. It has now formed the world's most consensus-building government: fiscal policy, monetary policy, and, of course, none of these "new" policies.