同学你好，该知识点来自沪江网校《英语零基础直达大学六级【听说升级版 3月班 】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
by then, by that time, from then on没有固定搭配的时态，可以和将来时、过去时等搭配。
By then, it was October and we were more than halfway through our tour.
那时已是10月，我们已经完成了行程的一大半了。
It had been supposed that by then Peter would be married.
人们一直认为到那时彼得应该结婚了。
By that time the steel output will have greatly increased.
到那会儿钢的产量将大大增加。
We become companion in misfortune from then on.
从那时起，我们就成了患难之交。

通常要说from then on 从那时起，而不是from then

祝同学学习进步~