Didn't you buy vs. Don't you buy: Understanding the Difference in English

'Didn't you buy' is a question asking if someone made a purchase. Example: 'Didn't you buy a new car?'

'Don't you buy' is a statement suggesting the person regularly purchases something. Example: 'Don't you buy coffee every morning?'

中文翻译：

'你不是买了吗？'是一个问句，询问某人是否购买了某物。例如：'你不是买了一辆新车吗？'

'你不是经常买吗？'是一个陈述句，暗示某人经常购买某物。例如：'你不是每天早上都买咖啡吗？'