Among the varieties you listed, sugar and PTA are more suitable than others. You must be active when choosing a speculation order, because it is easy to make a deal, or it is easy to make a deal, because the speculation order takes the winning rate as the guarantee of profit. If the transaction is not active, you will raise the price yourself when you make a deal. The price is very high, because you can't make much, but if the price is intermittent, your stop loss will be set high, and you have to make up a few losses, which is too big.