As far as the third factor is concerned,the history of science shows many instances in which the for

题目

As far as the third factor is concerned,the history of science shows many instances in which the force of authority has operated in such a manner as to build up an exceedingly powerful resistance to further investigation;in some cases centuries elapsed before this resistance was eventually broken down,as happened in cosmology,for example.
针对上面这句话,有个in which the force.,这个which前加的in是有什么用呢,请指教

答案

个人认为即使不加in,也正确,那么后面的从句就是关于instances的定语从句.加了In,就是说,从以往学术发展的历史来看有很多例子是关于.,in在这里是关于的意思,那么这成了状语从句.