为什么市盈率？市盈率是股票市场上一个重要的指标，用于评估公司股票的相对价值。市盈率通常被定义为公司的市场价值与其净利润之间的比值。英文翻译为：Why is the P/E ratio? The P/E ratio is an important indicator in the stock market that is used to evaluate the relative value of a company's stock. The P/E ratio is typically defined as the market value of a company divided by its net profit.

首先，市盈率可以帮助投资者判断公司的盈利能力。市盈率越高，意味着投资者需要支付更高的价格来获得公司每一元的净利润。因此，高市盈率通常意味着市场对公司未来的盈利预期较高。然而，市盈率并不是越高越好，因为过高的市盈率也可能意味着市场对公司未来的盈利预期过于乐观，或者市场存在泡沫。英文翻译为：Firstly, the P/E ratio can help investors judge a company's profitability. A higher P/E ratio means that investors need to pay a higher price to obtain each unit of net profit from the company. Therefore, a high P/E ratio usually indicates that the market has high expectations for the company's future earnings. However, a high P/E ratio is not always better, because overly high P/E ratios may indicate that the market's expectations for the company's future earnings are too optimistic, or that there is a bubble in the market.

其次，市盈率也可以用于评估不同行业和不同公司之间的相对吸引力。不同行业和不同公司的市盈率可能存在较大差异，这可能与其盈利前景、增长潜力、竞争优势等因素有关。因此，通过比较不同行业和不同公司的市盈率，投资者可以评估哪些行业和公司更具吸引力。英文翻译为：Secondly, the P/E ratio can also be used to evaluate the relative attractiveness of different industries and companies. The P/E ratios of different industries and companies may vary significantly, which may be related to their earnings prospects, growth potential, competitive advantages and other factors. Therefore, by comparing the P/E ratios of different industries and companies, investors can assess which industries and companies are more attractive.