The principle of transaction is price first, time first; The market price, that is, the current price of 2000. Hang more than 2500 orders, with 2000 priority price, 2500 empty orders are not closed. This is the general situation; If there are no other orders in the market, A buys at 2500, then B sells at 2500, and they make a deal at 2500. Dynamically, the principle remains unchanged.