(verb: to back up, to make a copy of [a disk]) Because I forgot to back up this document, I lost two days' work! Ich habe zwei Arbeitstage verloren, weil ich vergessen habe, diese Datei zu sichern! Tôi đã mất hai ngày làm việc vì quên sao lưu tập tin này!
à quên 
oh, I almost forgot 
Only when I got to my company did I discover that I forgot to bring my cellphone. 
Erst als ich in meiner Firma ankam, stellte ich fest, dass ich vergessen hatte, mein Handy mitzubringen.