If you trade copper, then you must be worried that the price will fall, and your selling profit will be reduced, or even you may lose money. Because futures prices usually follow the trend of spot prices, and futures can be short. Then when you are worried about the decline of copper price, you can short copper futures in the futures market. The maturity date is similar to the date when you sold it in spot copper, and the quantity is the same as that of your spot transaction. Then the price falls and the spot profit decreases, but the futures are profitable because they are sold at a high level and bought at a low level. Make up for the decline in spot profit and lock in your sales profit.

Do what futures worry about on the spot. Worried about the spot decline, short futures; If you are worried about rising, do more in futures.