放在句首引导从句是连词,如：The two of them have been close friends ever since they knew.他们俩认识后一直很要好.
如果接的不是句子,则是介词,如：Ever since his adventure in the mountains,he has been dining off the story.自从进山中探险以来,他一直靠这段经历维生.
而放在句末则是副词,如：
He came to London 3 years ago and has lived here ever since.他三年前来到伦敦,此后就一直住在这里.
He inherited his father's fortune and has lived like a pig in clover ever since.他继承了他父亲的财产,生活极为奢侈.