The gap is mainly affected by the external market. When the China futures market was closed, foreign countries were still trading. If there is a sharp rise or fall, there will be a big gap between domestic similar products. Such as gold, Shanghai copper, soybeans, fuel oil, etc. are easily affected by the external disk. Generally, the products that are not easily affected by the external market are mainly self-sufficient products imported from China, such as corn, cotton, sugar, strong wheat and hard wheat. In addition, rebar and wire rod are unique to China, and there is no external disk, and the trend is also very strong.