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.
ever since是从那一直到现在
Have you been living there ever since?
你是不是一直住在那里?
since then是从那以后
He's teach English since then.
从那时起他就教英语.