So if you sell, you are bearish. If you want to close your position, you must buy a list.

For example, a contract, 100 yuan. You thought it would fall, so you bought it.

Two days later, its price dropped to 50 yuan as you wish. At this time, you buy a hand.

Just earned (100-50)=50 yuan.

I bought it for the first time because I was bearish. So I sold it! That is, selling and opening positions.

The second time you buy, you have to close your position. So it's even. That is, buying and closing positions.