そう sou言(い)え()ば() ieba、肝(かん)心(じん)要(かなめ) kanjinkanameの no部(ぶ)分(ぶん) bubunを o何(なに)も() nanimo決(き)め()て()い()な()か()っ()た() kimeteinakatta。 Now that you mention it, we hadn't decided anything about the most crucial part. everyday conversation何も~ない (nothing)そういえば (now that you mention it)肝心要 (the crux)