translation.en: First, many studies asked women to report their symptoms retrospectively, looking to the past and relying on memory, which is known to inflate reporting of PMS compared to what's called prospective reporting, which involves keeping a daily log of symptoms for at least two months in a row.
translation.zh: 首先，很多研究要求女性 回溯报告她们的症状， 回顾过去，仰赖记忆， 我们已知这种方法会夸大事实； 与之相较的另一种方法叫做前瞻性报告， 被测者要每天记录发生的症状， 至少持续两个月的时间。