Wow, if the time interval between different contracts of the same variety is relatively short, then there are fewer variables in the middle, and the environment in which the two contracts are located is the same, and the market expectation has similar influence on the two varieties, so the two contracts will converge. If the time interval between two contracts is long, then there are more variables. Although the environment is the same, market expectations may have opposite effects on the two contracts, or the influencing factors of recent contracts and forward contracts may have different effects on each contract. Of course, if the whole environment is a bull market or a bear market, then the trends of different contracts are basically the same.