这些表达不仅自然流畅，还显得比较高级，适合在正式或非正式场合使用：
1. At one juncture
- 意思：在某个关键时刻；在某个阶段
- 例句：At one juncture, I had to make a difficult decision that changed my career path.
（在某个关键时刻，我不得不做出一个改变了我职业道路的艰难决定。）
2. On one memorable occasion
- 意思：在一个令人难忘的场合
- 例句：On one memorable occasion, I was invited to a royal gala where I met several celebrities.
（在一个令人难忘的场合，我被邀请参加了一场皇家晚宴，见到了许多名人。）
3. In a past experience
- 意思：在过去的一次经历中
- 例句：In a past experience, I had the opportunity to volunteer in a remote village, which was a life-changing event.
（在过去的一次经历中，我有机会在一个偏远村庄做志愿者，这是一次改变人生的经历。）
4. At a particular moment in time
- 意思：在某个特定时刻
- 例句：At a particular moment in time, I realized that I needed to take control of my own destiny.
（在某个特定时刻，我意识到我需要掌控自己的命运。）
5. On a specific occasion that stands out
- 意思：在一个特别突出的场合
- 例句：On a specific occasion that stands out, I was able to help a lost tourist find their way back to their hotel.
（在一个特别突出的场合，我帮助一位迷路的游客找到了回酒店的路。）
