同学你好，该知识点来自沪江网校《新概念英语1、2、3、4册连读【双旦特惠班】》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~
这里since是副词，作状语，意思是“(表示过去某事或某情况发生后不久又发生了另一件事)此后，后来”
His style of leadership has attracted increasing criticism among his supporters, many of whom have since left Central Office.
他的领导风格已经在他的拥趸中引起了越来越多的批评，很多人后来离开了总局。
We were divorced two years ago and she has since remarried.
我们两年前离了婚，之后她又再婚了。

祝同学学习进步~