The linkage relationship of the index is affected by three aspects.

1) The major stock index market moves first, that is, the leading index, such as the US stock index.

2) Index futures and index options are leading indicators of stock indexes.

3) The rotation relationship between the opening times of each continent.

After the U.S. index plummets, for example, the Dow Jones first pulls back to the neckline level of 25476, and then sees whether the neckline level can truly break through. If it cannot truly break through, it will go down to make a double bottom. If the double bottom fails, the support level Seeing the 15,000-point range, which is the 60-quarter moving average, finally the Dow Jones is a bull market in 2021.