A conjunction indicating that one event happens immediately after or almost as soon as another (often follows the past tense).
窓を開けたかと思うと、強い風が吹き込んできた。
No sooner had I opened the window than a strong wind blew in.
彼は席についたかと思うと、すぐに立ち上がって部屋を出て行った。
He had barely sat down when he stood up and left the room.
赤ちゃんが泣き止んだかと思うと、またすぐに泣き始めた。
Just when the baby stopped crying, it started again immediately.
An expression meaning 'when I think that...' or 'at the thought of...', indicating a reaction or feeling that arises on thinking about something.
久しぶりに故郷のことを思い出すかと思うと、急に懐かしさで胸がいっぱいになった。
When I thought about my hometown after a long time, I was suddenly filled with nostalgia.
彼のことを考えるかと思うと、笑顔が浮かんでしまう。
When I think of him, a smile comes to my face.