中文：

沃伦·巴菲特是一位著名的投资家，他的投资理念和价值投资法被广泛认可。巴菲特曾经多次表示，他会在一个公司或股票有长期投资价值的时候进行投资，而不是短期投机。那么，巴菲特是在什么时候买的呢？

首先，巴菲特的投资策略是价值投资。他会在一个公司或股票价格远低于其内在价值时进行投资。此外，他还会评估公司的基本面，包括财务状况、行业前景等，以确定该公司的长期投资价值。

其次，巴菲特会在市场下跌或恐慌时进行投资。他认为，在市场下跌时，许多优质的公司和股票也会出现下跌，这为价值投资者提供了更多的机会。因此，他会在市场下跌时寻找更多的投资机会。

最后，巴菲特的投资决策是基于长期投资价值评估的。他不会因为短期市场波动而改变他的投资决策，而是会坚持长期持有优质公司或股票。

总的来说，巴菲特的投资策略是在公司或股票具有长期投资价值的时候进行投资，并在市场下跌时寻找更多的投资机会。他的价值投资理念和长期持有策略，让他成为了全球著名的投资家之一。

英文：

Warren Buffett is a famous investor whose investment philosophy and value investing approach are widely recognized. Buffett has stated multiple times that he invests when a company or stock has long-term investment value, rather than short-term speculation. So, when did Buffett buy?

Firstly, Buffett's investment strategy is value investing. He invests when a company or stock price is much lower than its intrinsic value. Additionally, he evaluates a company's fundamentals, including its financial condition, industry prospects, etc., to determine the company's long-term investment value.

Secondly, Buffett invests during market downturns or panics. He believes that when the market falls, many high-quality companies and stocks will also experience a decline, providing more opportunities for value investors. Therefore, he searches for more investment opportunities during market downturns.

Finally, Buffett's investment decisions are based on long-term investment value assessments. He does not change his investment decisions due to short-term market fluctuations, but adheres to long-term holding of high-quality companies or stocks.

Overall, Buffett's investment strategy is to invest when a company or stock has long-term investment value, and to seek out more investment opportunities during market downturns. His value investing philosophy and long-term holding strategy have made him one of the world's most famous investors.