股市为什么会跌？这个问题的答案涉及到多个因素，以下是对这个问题的解析以及英文翻译对照：

首先，股市下跌可能是由于经济基本面的变化。当经济增长放缓或出现负增长时，企业的盈利能力和经营状况可能会受到影响，导致股票价格下跌。此外，通货膨胀、利率上升、国际贸易局势等宏观经济因素也可能对股市造成压力。英文翻译为：Why does the stock market fall? This question has many answers. Firstly, the stock market decline may be due to changes in economic fundamentals. When economic growth slows down or even turns negative, the profitability and operating conditions of companies may be affected, leading to a decline in stock prices. Additionally, macroeconomic factors such as inflation, interest rate increases, and international trade situations may also put pressure on the stock market.

其次，股市下跌可能是由于市场供需关系的变化。当市场上的卖方数量超过买方数量时，股票价格就会下跌。此外，如果投资者对市场前景持悲观态度，可能会导致股票需求不足，从而进一步推动股市下跌。英文翻译为：Secondly, the stock market decline may be due to changes in market supply and demand. When the number of sellers in the market exceeds the number of buyers, stock prices will fall. Additionally, if investors have a pessimistic outlook on the market, there may be insufficient demand for stocks, which will further push the stock market down.

最后，股市下跌还可能是由于政策因素的影响。政府的货币政策、财政政策和监管政策等都可能对股市产生影响。例如，如果政府采取紧缩政策导致流动性不足，可能会导致股票价格下跌。英文翻译为：Finally, the stock market decline may also be due to policy factors. Government monetary policy, fiscal policy, and regulatory policies may all have an impact on the stock market. For example, if the government adopts tight monetary policy that leads to insufficient liquidity, it may cause stock prices to fall.