happen的过去式 happened；
happenv.(尤指偶然)发生，出现；(作为结果)出现，发生；碰巧；恰好
Who can say what will happen next year?
谁能说得出明年会发生什么事？
She gave us her version of what had happened that day.
她从她的角度向我们描述了那天发生的事情。
She gave us her version of what had happened that day.
她向我们描述了她认为那天发生的事情。
