凡是表示“完全”的副词都可修饰by accident。比如英语不仅可以说quite by accident, completely by accident，而且可以说entirely by accident，purely by accident等。如：

Helen got into acting purely by accident.  海伦进入演艺界纯属偶然。

We met each other again completely by accident. 我们再次相遇，完全出于偶然。

We lighted upon the solution entirely by accident. 我们完全是偶然想到了这个解决办法。