Most contracts are active from June 5438, 2005 to September 2005 (agricultural products), and industrial products are different. They often change months, just like copper once a month. The trading volume is concentrated in a few months, some are for harvesting consumption, and some are because the domestic futures market is not active, so hedging and speculation are going to trade large contracts. Generally, the largest turnover is the main contract. As time goes by, funds are continuously transferred to new main contracts. The main trading volume of China futures market is concentrated in one contract, which shows that there are too few market participants and a strong speculative atmosphere. Comparing with the American market, you will find that the turnover is very high in many months.