In the near future, the car owner who has changed the gasoline pump or unloaded the gas pump will not panic if there is a gasoline smell in the car. It is likely that the residue has not been cleaned up after the removal of the vehicle. The probability of such a situation is small, and the general replacement cycle of the gasoline pump is 100 thousand kilometers. But the gasoline filter is connected with the gasoline pump. The replacement cycle is shorter and the gasoline pump needs to be removed when replacing. In this case, simply check the installation of the gasoline pump and clean the surrounding area. The accounting income follows the historical cost principle and the matching principle, which is conducive to the objective reflection of the business management responsibility of the enterprise management authorities. But, due to the historical cost principle inherent defects, especially according to the present value of revenue and expenses by historical cost line, makes the calculation of accounting earnings lack of inner logical unity, and the matching principle is difficult to carry out, so that the book value of assets can not reflect its real value, cost cannot be fully compensated. And the economic benefit is measured in the current value, which reflects the actual value of the asset, which is beneficial to the full compensation of the cost.