行ってた

was going, had gone; had been (somewhere)

→ 行く
行っ to go + て Te-form (conjunctive form) + た Past tense
verb · informal, past tense Uncommon #11,617
was going, had gone; had been (somewhere) Colloquial contraction of 行っていた.
JA: さっきまでどこに行ってたの?
EN: Where have you been until now?
Conjugation of 行く

どこへ行ってたの?

Where have you been?

— JUNO/ジュノ (2007)

昨日さ、公園に行ってたよね?

You went to the park yesterday, right?

どこ行ってた

Where have you been?

— Good Luck, Have Fun, Don't Die (2026)

パパ風船みたいなジュノどこへ行ってた?

Juno, who looks like a balloon, where have you been?

— JUNO/ジュノ (2007)

学校にでも行ってたんだろ

You must have gone to school or something.

— レオン (1994)

昨日の夜はトムと飲みに行ってたよ。

I went out drinking with Tom last night.

どこ行ってた?

Where have you been?

— ブエノスアイレス (1997)

荷物を送るのに、郵便局に行ってた。

I went to the post office to send a package.

どこへ行ってたのよ?

Where have you been?

— 人生スイッチ (2014)

もうずいぶん昔のことよく遊びに行ってたわ

That was a long time ago. I used to visit a lot.

— When Marnie Was There (2014)

どこに行ってた?

Where have you been?

— ベイビー・ブローカー (2022)

南フランスへ行ってた

I went to the south of France.

— アメリカン・ギャングスター (2007)

ずっと兄と行ってたんだが

I’ve always gone with my older brother, but…

— レザボア・ドッグス (1992)

どこへ行ってたんだ?

Where have you been?

— きっと、うまくいく (2009)

どこ行ってた一緒か?

Where had you been? Were you together?

— タクシー運転手 約束は海を越えて (2017)

先週は出張に行ってたよ。

I was on a business trip last week.

この教会によく行ってたなぁ。

I used to go to this church quite often.

うまいが…話してちょうだいどこへ行ってたの?

That’s good, but… tell me, where have you been?

— グッドフェローズ (1990)

今日、トムは本当に学校に行ってたのかしら。

I wonder if Tom really went to school today.