since then和 from then on有什么区别?

since then和 from then on有什么区别?
since then和 from then on有什么区别?

since then和 from then on有什么区别?
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,小威廉注定要献身魔术.
2.From then on ,the fairy weaver stayed in heaven ,and the cowherd stayed on earth .
从此,织女留在天上,而牛郎则待在人间.