中 => Throughout, all over, during the course of N5
Time
[事「こと」]だ => A is necessary/good (offering advice/suggestion) N3
Needs, Requirement
[最中「さいちゅう」] => In the middle of A N3
Time, Situation
[中心「ちゅうしん」]に => With A as the center N2
Miscellaneous
[事「こと」]ができる => Be able to A; can do A, Can A; be possible to A; N4
Causative, Passive, Volitional
に[限「かぎ」]った[事「こと」]ではない => It's not limited to A, it's not only A N1
Degree/ Level/Amount