Sudden reversal / immediate change
often beyond speaker’s control
Open details
Form: V-た + かと思 うと／かと思 ったら
Use when: A happens, then instantly B (often surprising/counter to expectation).
Contrast: とたん = “the very instant” of a single event; かと思うと = highlights the swift turnabout.
Avoid: your own intentional actions in sequence (“I did A and then I did B”).
Barely finished A → B happens instantly
“whether A finished or not”
Open details
Form: V-辞 書 形 + か + V-ない形 + かのうちに
Use when: B happens almost simultaneously with A finishing/starting.
Contrast: とたん emphasizes surprise; か〜ないかのうちに emphasizes time overlap.
Almost happened (near-miss / narrowly)
often with もう少しで／危 うく
Open details
Form: V-辞 書 形／V-ない形 + ところだった
Use when: something was on the verge of happening (but didn’t) or nearly didn’t happen.
1) 〜かと思うと・〜かと思ったら — sudden reversal
A is followed immediately by B, often unexpected or opposite. Usually used for changes outside the speaker’s control.
Form: V-た + かと思 うと／かと思 ったら
Collocations: 途端 に／一転 して／急変 する
No sooner had it stopped raining than it started again.
The moment the CEO announced his resignation, the market became unsettled.
こどもは
A child goes from crying to laughing in an instant.
Pitfall: Avoid “I did A and then I did B on purpose.” Use neutral/externally-caused changes.
2) 〜か〜ないかのうちに — almost simultaneously
B happens at virtually the same time as A (whether A has finished or not).
Form: V-辞 書 形 + か + V-ない形 + かのうちに
Pattern: AかAないかのうちにB
No sooner did the bell ring than the students rushed out.
Orders flooded in almost the instant sales began.
I got a reply almost the moment I hit send.
Note: Often used with verbs of start/finish like 立つ／開く／着く／終わる.
3) 〜ところだった — almost (but didn’t)
Expresses a near-miss or a narrowly avoided outcome. Use with adverbs like もう少しで／
Form: V-辞 書 形 + ところだった ／ V-ない形 + ところだった
Nuance: speaker’s retrospective relief/regret.
もう
I almost missed the deadline.
I nearly fell down the stairs.
バスに
I almost didn’t get on the bus, but my friend stopped me.
Pitfall: Don’t pair with outcomes that actually occurred; it describes what almost happened.
Quick contrasts & pitfalls
- かと思うと = instant reversal after A. Avoid “my intentional actions”.
- か〜ないかのうちに = B occurs at the boundary of A finishing → near-simultaneous.
- ところだった = “nearly did / nearly didn’t.” Often with もう少しで／危うく.
- とたん(に) vs かと思うと: both sudden; とたん = the exact instant & surprise; かと思うと = swift turnabout.
- Use varied subjects/events (weather, announcements, flows of people) to sound natural at N2 level.
