ever since 作为连词=since 完成时态---- ever since +主+动词简单过去式 例：i have known him ever since he was a child. 他从小我就认识他了。 这种用法同since 差不多，不过 ever since 比 since 用得少。 再如：we have lived in shanghai ever since we came to china.(自从我们来到中国之后就住在上海。) then本身是个过去的时间点，since then表示从那个时间点到现在的情况，一般是现在完成时。 比如 i have not gone there since then.