いつのまに
when; at what point
Also written 何時の間に
Expression, Adverb
あれ？いつの間まに雨あめが降ふってたんだろう。全然ぜんぜん気付きづかなかった。
Eh? When did it start raining? I didn't notice at all.
「あれ？ここにパン屋やさんなかった？」「それなら、とっくの昔むかしに潰つぶれちゃったよ」「うそ、いつの間まに？」「半年はんとし前まえぐらいかな」
"Huh, didn't the bakery store use to be here?" "Oh, it went bankrupt a while ago." "Really? When did that happen?" "I think it was about half a year ago."