They came to a classroom,in the front of which sat a student.
这个倒装句的定语如何理顺呢?
They came to a classroom, in the front of which sat a student.
这个非限制性定语从句使用了完全倒装结构。试比较：
A student sat in the front of the classroom.
本句中sat为不及物动词，后接必具性地址状语。当出于某种缘由必具性状语前置（即移至句首），且主语不是人称代词时，则需要完全倒装：
In the front of the classroom sat a student.
In the front of the classroom a student sat.
假如主语为人称代词，则不倒装：
In the front of the classroom he sat.
In the front of the classroom sat he.
网友的这个句子中，关系代词指代classroom，作介词的宾语，且介词短语需要前置，故从句主谓倒装。
