そしたら

In a sentence

• 友達が勧めてくれた本を読んだ。そしたら、とても面白かった。

  I read the book my friend recommended, and it was very interesting.

  In this context, そしたら is used to indicate a sequence of events, where the action of reading the book precedes the realization of its interest.

• 駅に行きました。そしたら、店が休みになっていました。

  I went to the station, but the shop was closed.

  Here, そしたら introduces the result or unexpected discovery following the action of going to the station.

• 勉強する時間が少しありました。そしたら、試験前に復習ができました。

  I had some time to study, so I was able to review before the exam.

  In this example, そしたら shows the logical result or outcome due to the preceding event of having time to study.