SuGoiSuす語彙すGrammar › N2 · 02 Time and sequence
〜か〜ないかのうちに: just as; no sooner than
N2 · 02 Time and sequence
Says that a second action started almost at the same moment the first one began or ended.
Verb dictionary form + か + verb ない form + かのうちに, e.g. 寝るか寝ないかのうちに. Also with た-form: 着いたか着かないかのうちに. The two events are nearly simultaneous. Usually describes a past or habitual event.
Examples
ベッドに入るか入らないかのうちに、眠ってしまった。
I fell asleep almost the moment I got into bed.
授業が終わったか終わらないかのうちに、生徒たちは教室を飛び出した。
The students rushed out of the classroom the instant class ended.