〜かと思うと
No sooner than 〜かと思うと
Meaning
"No sooner had ~ than ~", "just when you think ~" — two events tread on each other.
Formation
[verb, plain past] + かと思うと / かと思ったら
Notes
Reports an observed surprise, so it is about someone else, not yourself, and the second clause cannot be a plan or request. 泣いたかと思ったらもう笑っている. Very close to 〜たとたん, but this one stresses how fast the reversal was.
Examples
赤（あか）ちゃんは泣（な）いたかと思（おも）うと、もう笑（わら）っています。
No sooner does the baby cry than it is laughing again.
Breakdown
急（きゅう）に暗（くら）くなったかと思（おも）ったら、雨（あめ）が降り出（ふりだ）した。
The sky had barely darkened when it began to rain.
Breakdown
帰（かえ）ってきたかと思（おも）うと、また出て行（でてい）った。
He had barely got home before he went out again.
Breakdown
座（すわ）ったかと思（おも）ったら、もう眠（ねむ）っていました。
He had scarcely sat down before he was asleep.
Breakdown
春（はる）が来（き）たかと思（おも）うと、もう夏（なつ）のような暑（あつ）さです。
Spring had hardly arrived and it is already summer heat.
Breakdown
⚠️ Often confused with
〜た後で / 〜後
After doing 〜後で
"After doing ~". Attach to the ta-form of a verb, or a noun + の. Note the contrast with...
〜てから
After doing (and then) 〜てから
"After doing ~ (and only then ~)". Emphasizes that action B happens AFTER action A is comp...
〜前に
Before doing 〜前に
"Before doing ~". Attach to the dictionary form of a verb or a noun + の. The action AFTER...
〜たとたん（に）
The moment 〜たとたん
"The moment ~", "just as ~" — the second event follows instantly and unexpectedly.
〜次第
As soon as 〜次第
"As soon as ~", "the moment ~ is done". Formal, and always about the future.
〜以来
Ever since 〜以来
"Ever since ~" — a state that has held continuously from a past point until now.
〜たびに
Every time 〜たびに
"Every time ~", "whenever ~" — the second thing happens on each occasion of the first.
〜ぶり
After an interval 〜ぶり
"After an interval of ~" — how long it has been since this last happened.
〜上で
After (formal) 〜上で
"After ~ing (and on that basis)" — a deliberate step taken before deciding.
〜ところに / 〜ところへ
Just as / right when 〜ところに
"Just as ~", "right when ~" — something arrives at exactly that moment.
〜に際して
At the time of 〜に際して
Formal "on the occasion of ~", "at the time of ~" — used as something significant begins.
〜てはじめて
Only after 〜てはじめて
"Only after ~", "not until ~ did I …".
〜てからというもの
Ever since then 〜てからというもの
"Ever since ~" — a turning point after which things have stayed changed.
〜に先立って
Prior to 〜に先立って
"Prior to ~", "in advance of ~" — a preliminary step before a major event.
〜際（に）
On the occasion of 〜際（に）
A formal "when ~", "on the occasion of ~".
〜が早いか
The instant that 〜が早いか
"The instant ~ happened, ...", "no sooner ~ than ...".
〜や否や
Scarcely when 〜や否や
"As soon as ~", "scarcely had ~ when ..." — the two events are almost simultaneous.
〜そばから
No sooner done than undone 〜そばから
"No sooner is ~ done than (it is undone)" — the effort is immediately cancelled out.
〜なり
Immediately upon 〜なり
"The moment ~", "immediately upon ~ing" — one action leads straight into an unexpected nex...
〜を境に
Marking the turning point 〜を境に
"With ~ as the dividing line", "ever since ~" — a clear before and after.
〜がてら
While also doing 〜がてら
"While ~ing", "taking the opportunity of ~ing to also ..." — two purposes in one outing.
〜間際に
On the verge of 〜間際に
"Just as ~ is about to happen", "at the very last moment before ~".