Take "price first, time first" as the principle. "Price priority" means that high-priced buying declaration takes precedence over low-priced buying declaration, and low-priced selling declaration takes precedence over high-priced selling declaration.

"Time priority" means that the buying and selling direction and price are the same, and the first applicant has priority over the last applicant. Determine the order according to the time when the exchange host accepts the declaration.