when (someone) enters
ベッドに入るとすぐ彼は眠り込んだ。
As soon as he got into bed, he fell fast asleep.
店内に入ると、私はほっとした。
I felt relieved as soon as I entered the store.
彼女は教会に入ると、ひざまずいた。
When she entered the church, she knelt down.
なんで汗が目に入ると痛いの？
Why does it hurt when sweat gets in your eyes?
町に入ると塔を見失ってしまった。
When I entered the town, I lost sight of the tower.