After all, with tighter regulation and tight capital, high interest rates and high limits mean high risk, but investors should also be careful not to put money in one basket. 3. The cost of accounting earnings is listed in historical cost. Due to the current accounting practice in the enterprise asset is measured at the historical cost in, with the cost nature is the historical cost has been derived from the law of the transfer, so as to determine the income is an important factor in the cost and the historical cost. It is not obvious in some analyses, but it is important to note that economic profits include opportunity costs. The profit of an entrepreneur (normal profit) is usually positive, but economic profit can be either positive or negative (loss). That's why the opportunity cost is included: in a completely competitive market, when marginal cost equals marginal revenue, profit maximization or loss minimization conditions arise. If the market price is lower than the total average cost, which means that the economic profit is negative, the entrepreneur needs to compare the value of the loss and the average variable cost. If the business continues to operate, the negative economic profit must not be lower than the average variable cost, otherwise the entrepreneur would rather shut down the company than continue to take the loss. Solution: as long as the gasoline in the tank is exhausted, the extra gasoline vapor in the tank can be fired into the cylinder by the negative pressure of the engine, and no gasoline vapor will overflow. Gasoline sales in the United States are mainly due to competitive gasoline prices and rising fuel efficiency, with a high seasonal impact. Population and cultural factors are also important factors that influence the trend of gasoline consumption in the United States, according to Jill Mislinski, an analyst with Advisor Perspectives.