〜かと思うと／〜かと思ったら

Meaning

Expresses that no sooner does one think something has happened than another thing follows immediately. Describes two events occurring one after another without pause, or surprise at a sudden change. Used as in 「泣いたかと思うと、もう笑っている」.

Examples

空が暗くなったかと思うと、急に雨が降り出した Just when the sky turned dark, it suddenly started to rain.
赤ん坊は泣いたかと思うと、すぐに眠ってしまった The baby was crying one moment and asleep the next.
帰ってきたかと思ったら、また出かけていった I thought he had come home, but he went out again.
株価が上がったかと思ったら、翌日には下落した The stock price went up, only to drop the very next day.