かと思うと／～かと思ったら (ka-to-omou-to): No sooner than; just when
～かと思うと／～かと思ったら (ka-to-omou-to)
Meaning
No sooner than; just when
Formation and usage
Vた + かと思うと／かと思ったら
Notation: N = noun; V dictionary = dictionary-form verb; V stem = the stem before ます; plain clause = plain-form clause; negative stem = the form before ない. Follow the attachment shown above.
Explanation
Describes a sudden change after an observed event, rather than the speaker's own planned decision.
Examples
会議が始まったかと思うと、急に警報が鳴った。
No sooner had the meeting begun than an alarm suddenly sounded.
試験が始まったかと思うと、急に警報が鳴った。
No sooner had the exam begun than an alarm suddenly sounded.
研修が始まったかと思うと、急に警報が鳴った。
No sooner had the training session begun than an alarm suddenly sounded.
発表会が始まったかと思うと、急に警報が鳴った。
No sooner had the presentation event begun than an alarm suddenly sounded.
面接が始まったかと思うと、急に警報が鳴った。
No sooner had the interview begun than an alarm suddenly sounded.
How related patterns differ
が早いか, なり, and や否や narrate an immediate following event. か～ないかのうちに suggests the first may not yet have finished. そばから often describes an action being repeated or undone, rather than simply a sequence.