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". All in all, Mr Trump is like a populist in the populist outfit - a pluto-populist. But why does his base allow him to avoid pursuing policies that hurt them mainly? According to an opinion, he is betting on social conservatives and white blue-collar supporters in rural areas to nationalism and religious sentiment and antipathy towards the coast of secular elite vote, on the basis of not for their own economic interests. This refers to the industrial handicraft industry from the feudal society to the early stage of capitalism. In the 16th century to the 17th century, some western countries of the feudal social system to the system of capitalism, capitalist primitive accumulation is accelerated, deprived of farmers' land on a large scale, make cottage industry collapse, sharply to capitalism works system transformation. Industrial handicraft industry is the embryonic form of enterprise. In 1946, the famous British economist J.R. hicks, in value and capital, developed the concept of income into a general concept of economic gain. He argues that the real purpose of computing revenues is to make people aware of the amount of money they can spend without making them poorer. Accordingly, he gave a generally accepted definition of "the maximum amount of consumption that a person can spend at the end of the term, at the same level of prosperity". Hicks's definition, though primarily for personal gain, applies to businesses as well. In the case of the enterprise, according to this definition, the enterprise income can be understood as the maximum amount that can be allocated in the enterprise cost accounting period under the same amount of capital at the end of the term and the beginning of the period. 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. According to the engine displacement, divided into a miniature (1 liter), light level sedan (1-1.6 liters), intermediate (1.6-2.5 litres), senior sedan (2.5 4 liters), limousine (4 liters).