What do you mean by how long the futures are?
In China, the difference between futures and stocks is that stocks can only be long, and futures can be long or short. In stock trading, you must buy stocks first, and then sell stocks. If the stock price rises during this period, you can make money; Unlike futures, you have two choices: 1, like stocks, buy futures first and then sell them when the futures price rises, so that you can make money. This is called duo. 2. Short and long are different. You should choose to sell futures first, even if you don't have futures in your hand. After the futures price falls, you can buy futures, which can make money. This is called emptying. Looking at futures correctly, both ups and downs can make money, but the profit and loss are the same. If you read the futures wrong, you may lose both, so please choose carefully.