とした

[Andromedashun]

What exactly is とした? For example:
助詞を中心とした問題

 

[nekojita]

When Xとする forms are used as modifiers, they are often in past tense. This is that vague form of とする which can be "to take as/set as/treat as/make..."

助詞を中心とする - to concentrate on particles/make particles the focus.
助詞を中心とした問題 question(s) which.... (etc)

 

[Andromedashun]

Oh wow, thanks!