Please come upstairs. People are asking about substitutes for futures delivery, not substitutes in real life. For example, for example, the standard cotton delivery product is 328b (Grade 3, cashmere length 28), but sometimes this standard cotton quantity may not be enough, so lower-grade goods are allowed to be delivered. These are substitutes. However, there is a rule that if the grade is high, you can make up some money, and if the grade is low, you should make up some money on the basis of the standard grade. For example, the regulation of cotton is that the second-grade cotton can be lifted by 300 yuan, and the fourth-grade cotton can be discounted by 450 yuan.