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! It doesn't seem to be too much of a market to really focus on learning or learning about the importance of learning. More and more, I feel that learning is to keep to the only way to do it for a long time in the market, continuous learning can bring something new to you constantly, in a sense, the ability of learning will be able to represent your trading ability and analysis ability. Because economists understand earnings as actual material wealth increase, accounting experts think the output value of more than the difference between the input value is profits, there is a contradiction and two kinds of income concept. The specific performance is: According to the latest standard GB/T 3730.1-2001, cars are mainly divided into passenger cars and commercial vehicles. Before that, what is the nature of the enterprise itself is an issue that has been ignored by traditional microeconomic theory. In the traditional microeconomic theory, is the manufacturer's production process as a "black box", namely enterprise is abstracted into a from input to output a "black box" of the pursuit of profit maximization.