開いてた

was open

→ 開く
開い to open; to open up + て Te-form (conjunctive form) + た Past tense
verb · informal, past tense Rare #43,912
was open Colloquial contraction of 開いていた.
JA: 窓が開いてた。
EN: The window was open.
Conjugation of 開く
Indicative past
開かなかった開いてた

ドアは開いてたの?

Was the door open?

ドアが開いてたこの子は?

The door was open. What about this kid?

— どん底作家の人生に幸あれ! (2019)

救急車が到着したとき開いてた?

Was it open when the ambulance arrived?

— 落下の解剖学 (2023)

突然現れた門が開いてた

The gate that suddenly appeared was open.

— 28年後... 白骨の神殿 (2026)