那是我们都回不去的从前那时我们都到不了的永远
[nèi shì wŏ men dōu huí bù qù de cóng qián nèi shí wŏ men dōu dào bù le de yŏng yuăn]
Reflects on an irretrievable past where love and commitment felt like 'forever,' suggesting feelings of nostalgia for a time that now seems unreachable or unattainable.