And their original meanings are long since forgotten.

其原有意义早已被遗忘。

youdao

Why is it that one sight, sound, or smell can sometimes trigger a flood of memories of some experience which we'd long since forgotten?

为什么某个特定的场景、声音或气味，会不时引发我们对某些早该忘记的经历的如潮回忆？

youdao

She had met too many people in the past year and had long since forgotten Hung-chien. After he introduced himself, she said feelingly in a sweet girlish voice, "Oh, yes!"

她一年来见过的人太多，早忘记鸿渐，到鸿渐自我介绍过了，她娇声感慨道：“记得！

youdao

And their original meanings are long since forgotten.

VOA: special.2010.02.14

An inspired musical and literary accomplishment, the result weaves together the sights and sounds of an America long since forgotten.

NPR: A Dustbowl Lament from an American Chameleon

And while I have long since forgotten how to solve a differential equation, I did learn how to drink responsibly (no tequila shots on an empty stomach).

FORBES: Grownup Training

Both are not only regular but heavy Internet users, who couldn't do their jobs without it, and both have long since forgotten their dismissal of the medium they now can't do without.

FORBES: The Addictive Internet