By pure coincidence my boss flew on the same plane as me.

纯属偶然，我的上司跟我乘同一架飞机。

youdao

Within a week, by pure coincidence (or was it?), three people mentioned to me that they knew Fred.

不到一周，完全巧合（真的是吗？），有三个人向我提起他们认识弗莱德。

youdao

At the moment the press decided that Al Gore and George W. Bush would be the major party nominees in the next campaign for the White House, I was, by pure coincidence, wondering idly whether Bill Bradley is too tall to be President.

CNN: Should Bradley stoop to conquer?