the best friends 是大家比较熟悉的用法，从字面意思也可以看出，它表示“最好的朋友”。至于 the best of friends，它的用法稍有不同。根据《柯林斯COBUILD高阶英汉双解学习词典，the best of friends 的解释是：If two people are the best of friends, they are close friends, especially when they have had a disagreement or fight in the past. 根据该解释，该短语的意思是：如果两个是the best of friends，那们就是亲密的朋友，尤其是当他们过去有过不同意见分歧或吵架。由此可以看出，the best of friends 既可指普通意义的“亲密朋友”“挚友”，也可指（且尤其指）冰释前嫌后的亲密朋友。例句如：

We became the best of friends and he influenced me deeply. 我们成了最好的朋友,他深深地影响了我。

In spite of their quarrel, they remain the best of friends. 尽管有过争吵，他们仍是最好的朋友。

Despite their different personalities, they became the best of friends. 尽管个性不同，他们还是成了最好的朋友。

They may have been the best of friends when they were younger but there’s no love lost between them now. 他们在年轻时曾经是最好的朋友，但是现在却彼此厌恶。