2. P45 forms are in four parts, part 1 is retained with the issuing employer and the employee retains part 1 A and may hand parts 2 and 3 for the new employer. The new employer cannot make use of the P45 tax details unless both parts are given over. If either part 2 or 3 with the P45 form is missing then this employee must be asked to complete the Inland Revenue P46 form. 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. 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. HM, Liverpool Economic profits in perfect competition and monopolistic competition market has a special purpose, a positive profit can attract more enterprises to enter the market, increasing competition and push the market equilibrium price low, exclude some enterprises lack of competitiveness in the market, to achieve long-term equilibrium; On the contrary, negative economic profit can eliminate some of the original enterprises in the market, because the supply is reduced, the market equilibrium price will be pushed up, and the long-term equilibrium will be achieved. The result of the two cases is that economic profits disappear from each manufacturer and the manufacturer's total income is at the lowest point of average cost.