The "empty" and "long" in short positions and long positions refer to short positions and long positions respectively, that is, the futures market is biased towards short positions or long positions. Biased to bears, bears are strong, futures prices are in a state of decline, and excessive is the opposite.

Short position: Although the stock price is relatively high at present, investors are not optimistic about the stock market prospect and expect the stock price to fall, so they sell the stock at a relatively high price and buy it when the stock falls to a certain price to obtain the difference income.

Long position means that investors are optimistic about the stock market and expect the stock price to be bullish, so they buy the stock at a low price and sell it when the stock rises to a certain price to obtain the difference income.