我來幫您回答：
1、since ever 翻譯為自從,與現(xiàn)在完成時態(tài)或過去完成時態(tài)連用.
（這與ever since 略有不同,ever since+ 過去時的句子：◆ever since I was at school .自從我上學(xué)以來.）
◆ He has lived there since ever.=Since ever,he has lived there.從那以后,他就住在那兒.
2、since then 意思是：從那以后直到現(xiàn)在,用于現(xiàn)在完成時.◆ I saw them at Christmas but haven't heard a thing since then.
◆ That was years ago.I've changed jobs since then.
所以他們的差別就在于用法不一樣.學(xué)習(xí)語言不能只記意思,還要看用法,所以多差字典哦!
請點贊,你的鼓勵將是我繼續(xù)回答問題的動力!