多年来他一直为改善公路安全而奔走——你不得不钦佩他的坚持不懈。

He has been campaigning for better highway safety for years - you have to admire his ___persistence.

对数月努力和坚持的回报终于到来了。

A reward for months of effort and ___persistence had at last arrived.

尽管多次尝试解决问题，但问题的持续存在令人沮丧。

Despite numerous attempts to resolve the issue, the ___persistence of the problem is frustrating.