That view represents a significant shift from the historical—which the grant of corporate privilege was to advancepublic purposes such as building roads, bridges, and canals.

以上源于一篇專八改錯題，我覺得錯誤點是在于historical后面缺一個名詞成分，但參考答案是把which改成where，請問各位老師，為何參考答案要如此改？

where 引導的定語從句修飾the historical. 假如用which, 沒辦法和前面構成修飾關系。the historical 是定冠詞+形容詞的一種表達方法，其實等于名詞用途， 如the rich, the beautiful, the natural. 當然假如你加個詞，只須語境允許也可以，如：the historical roles