1. It was great to run into an old acquaintance at the grocery store.
(スーパーで古い知り合いに会えて嬉しかった。)

2. I bumped into an old acquaintance from high school while out for a walk.
(散歩中に高校時代の古い知り合いに出くわした。)

3. I reconnected with an old acquaintance from my previous job on LinkedIn.
(以前の仕事の古い知り合いとLinkedInで再繋がりした。)

4. Catching up with an old acquaintance over coffee was a nice way to spend the afternoon.
(コーヒーを飲みながら古い知り合いと近況を話すのは午後を過ごす良い方法だった。)

5. My old acquaintance invited me to their housewarming party next weekend.
(古い知り合いが来週末の新築パーティーに私を招待してくれた。)

6. It's always a pleasant surprise to hear from an old acquaintance after so many years.
(長い年月が経ってから古い知り合いから連絡を受けるのはいつも嬉しい驚きだ。)