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
[中心「ちゅうしん」]に => With A as the center N2
Miscellaneous
[代「か」]わり => Not A, but B, B in place of A, Instead of A, B; In exchange for A, B N3
Comparison, Exchange