[中心「ちゅうしん」]に => With A as the center N2
Miscellaneous
中 => Throughout, all over, during the course of N5
Time
[最中「さいちゅう」] => In the middle of A N3
Time, Situation
ものの => Although A... N2
Contrast,Surprise
の => Question N5
Particles
ぐらいのものだ => Only A N1
(Not)only , (Not) even
もの => Because of A N2
Reason, Result, Response
たもの => Used to N3
Sentence Endings
の => Turn sentence into question N4
Sentence Endings
の => A kind of question N3
Sentence Endings
ので => Because A, since A N4
Cause and Effect
の+ [至「いた」]り => Very A N1
Degree/ Level/Amount