我早就忘了我们上次见面吵了些什么。（long since)

I have long since forgotten what we quarrelled about last time we met.

long since:

ad. 很久以前(早已,久已)

例句与用法:
1. Long ago; long since.
很久以前；往昔

2. His study is a chaos: his house keeper has long since given up trying to put his papers in order.
他的书房乱七八糟，他的管家早已放弃为他整理文件了。

3. It has long since been satisfactorily established that a high executive does not have a large vocabulary merely because of the opportunities of his position.
长期以来人们就有呈个想当然的看法：高级行政管理人员不会有很大的词汇量，因为处不那个位置上，他有的是机会。

4. He has long since been recognized as a great playwright.
他早就被公认为伟大的剧作家了。

i already forgot what we had quarrelled about long since we met last time.