[中心「ちゅうしん」]に => With A as the center N2
Miscellaneous
を中心に => focused on; centered on~ N2
~しいしい => Every once in a while... (Repeat situation) N1
Repetition, habit
らしい => It looks like N3
Situation
いたします => to do (polite form of します) N4
てもよろしいでしょうか => May I... N4
Allow
いつしか => before one knows N2
Accept, agree
しか~ない => only; nothing but N4
だけしか~ない => only N3
たいして…ない => ~is not much of~ N3
Emphasis on degree
いかにも…らしい => indeed; really; truly N3
Accept, agree
もしかすると/もしかしたら~かもしれない => perhaps; maybe; perchance; by any chance ~ N3