I happened to be at home.

我凑巧在家。

《新英汉大辞典》

I happened to be at the station when he arrived.

他到达时我恰好在车站上。

《新英汉大辞典》

I happened to be standing next to a Marine officer, with whom I made small talk.

站在我旁边的是一位海军陆战队的军官，我们简单的聊了几句。

youdao

So now thankfully I found the lightest one which happens to be this guy here and so what's just happened?

现在我找出了最轻的，它就是,这个杯子，那么刚刚发生了什么呢？

哈佛公开课 - 计算机科学课程节选

Now I could have made a key, keys don't have to be strings, but as it happened, I didn't.

现在我可以建立一个键了，键并不一定是字符串，但这儿既然已经是字符串了。

麻省理工公开课 - 计算机科学及编程导论课程节选

What happened subsequently can, I think, be traced to Derrida's lecture.

我认为之后的事，可以追溯到德里达的演讲。

耶鲁公开课 - 文学理论导论课程节选

"I happened to be at the right spot at the right time, " Maltz said.

WSJ: Syracuse rallies to beat Denver in lacrosse semis

Some months later, I happened to be in a restaurant in the Bahamas with some members of my family.

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The next morning, I happened to be the first car to the junction after the lights had gone red.

BBC: Lines painted in early Spring...