Keynes argued that savings and investment were two interdependent variables, not two independent variables. Hybrid cars, which add an internal combustion engine to pure electric vehicles, aim to reduce the pollution of cars and improve the mileage of pure electric vehicles. Hybrid vehicles have serial and parallel structure. Moment of torque Mooney and si prowse in its around the main accounting principles for enterprises ", not only emphasize to determine profits in a timely manner, and emphasizes the necessary through division operating earnings, the gains and the impact of price changes, to improve the comparability of financial statements and understandability.