[後「あと」]で => After V1, V2 N5
Time
たが[最後「さいご」] => Once A occurs, B happens N1
Information, Report
[一方「いっぽう」]だ => Change A continues, A does not stop N2
Miscellaneous
[一方「いっぽう」] => On one hand A, on the other, B; Although A, at the same time, B N2
Contrast,Surprise