While I didn’t see you with 〜うちに


Grammar Explanation

よつばと! » Volume 1 » Page 11

Jumbo arrives to help Yotsuba and her father move into their new home.

よつば:
「しばらく見ないうちにまた大きくなった!」
“You’ve grown bigger since I last saw you!”
Literal: “During the time I didn’t see you, you’ve gotten bigger!”
ジャンボ:
「お?どこでおぼえたそのセリフ」
“Oh? Where’d you pick up that line?”