They met by pure chance.

他们相遇纯属偶然。

《牛津词典》

I came on this idea by pure chance.

我有这个想法纯偶然。

youdao

I met him by pure chance.

我完全是偶然碰到他的。

youdao

I met him by pure chance.

我遇见她完全是偶然的。

youdao

By pure chance he found the book he needed.

他纯属偶然发现了他需要的那本书。

youdao

By pure chance he found the book he needed.

他纯属偶然发现了他需要的那本书。

youdao