Key areas can be resistance or support positions. Resistance or support is a general term, such as structural positions, supply and demand areas, Fibonacci retracement lines, trend lines, previous highs and lows, etc. There are a lot of funds making orders based on these positions. There are a lot of buy orders and active buy orders, as well as short-term profit-taking orders, which can have a significant stop effect on prices. The larger the time period of these key areas, the greater the short-term price fluctuations. When the sharp rise and fall of the K-line hits here, the possibility of an instant rebound is high.