In the trading system, there are many varieties of futures contracts, the same kind of futures contracts and different months, these actually show the expiration of the varieties of delivery of the month, such as sugar, its delivery month is 1, 3, 5, 7, 9, November, from the system we can see the sugar pendant contracts are sugar 1105, sugar 1107, sugar 1109, sugar 1111, sugar 1201, sugar 1203, sugar 1205 and so on these contracts. 1201, sugar 1203, sugar 1205 and so on these contracts. In these contracts we can judge from the volume of which is the main contract, from the corresponding current month we can judge which is the near-month contract (near delivery), which is the far-month contract.