"Look" of "bearish" refers to investors' judgment on the future market development, while "do" and "empty" represent investors' evaluation of the systemic risks brought by "buy" or "sell" behavior. Therefore, to put it simply, "bullish" and "bearish" are investors' subjective judgments on the risks of the market system, and "long" and "short" are rational choices of market operation behaviors (buying and selling) based on this judgment.