题目内容：

since then和 from then on有什么区别?

优质解答

since then一般用在完成时态1.But since then nothing has happened .但自那以来,什么都没有发生.from then on用于过去时态和完成时态1.From then on ,magic had to be young William 's life .从此以后,小威廉注定...