Hi, Actually we use “很久以前” more frequent, whenever you want to express a long time ago( I think at least more than 10 years) you can use it. As for "很早以前"，usually there are sentences before and after it. For example" 其实那件事是很早以前发生的=actually it hap pened a long time ago “很早已经” in Chinese it's not a fixed sentence. we don‘t put 很早and 已经together（of course in a long sentence they can coexist but not “together”） 早 in Chinese usually means ’early‘。 久 in Chinese means a long period of time and ancient as well both two words might have same meaning if they are added with other words：很早以前=很久以前（it depends on the meaning of the sentence） a little tips：in Chinese there are a lot of situations that can't be understand，compared to many other languages Chinese tends to have less ’logical regulations‘，so just remember them in heart and don't spend too much time on “ why”（even Chinese don’t know why，hahaha）

HI 在中文里，一般来说“久”比“早”可以指代更久远的时间。有的时候（in some occasions）”很早以前“=”很久以前“ 举个例子: 1、很久以前 （1）很久以前，有一个国王，他住在城堡里。(Long long ago）（可能是传说，可能是几百年前的事情）（在这个语境下，我们一般不使用“很早以前”，更不可能使用“很早已经”） （2）上一次见到你已经是很久以前的事情了。（两人可能好几年、十几年没有见面了） 2、很早已经 明天就要交论文了，但是我一点都不担心，因为我很早的时候就已经完成了它。（可能几周前就已经写好了论文） 3.很早以前 上一次见到你是很早以前（=很久以前）的事情了。（but I dont use 很早以前 very often) 希望我的答案对你有帮助。Hope my answer could help you.