第一个中文意思是，两天前

造句

Nealy disappeared two days ago， several miles away from any of the fighting.尼利两天前失踪了，离任何一个战场都有几英里。

by accident中文意思是，偶然意外地

She discovered the problem by accident during a visit to a nearby school.她在去附近一所学校参观时偶然发现了这个问题。