何をしてた

what were you doing

→ 何
phrase Uncommon #12,681
what were you doing An informal past-tense form of 何をしていた. The subject depends on context, so it can also mean “what was he/she doing” or “what were they doing.”
JA: 昨日の夜、何をしてた?
EN: What were you doing last night?

何をしてた?

What were you doing?

— ダイ・ハード (1988)

昨夜は何をしてたの?

What were you doing last night?

トムは先月、オーストラリアで何をしてたの?

What was Tom doing in Australia last month?

ハンスの奴何をしてたんだ…

What the hell was Hans doing…

— ダイ・ハード (1988)

何をしてたんだ?

What were you doing?

— ロード・オブ・ザ・リング/王の帰還 (2003)

そこで何をしてたの?

What were you doing there?

妻の菊仙は以前何をしてた?

What did his wife, Kikusen, do before?

— さらば、わが愛/覇王別姫 (1993)

連中がそこで何をしてたかわかるか?

Do you know what they were doing there?

— レザボア・ドッグス (1992)

捨てるのはもったいないから今日は何をしてたの?

It would be a waste to throw it away. What were you doing today?

— ジョジョ・ラビット (2019)

パンク小僧が何をしてたかな

I wonder what that punk kid was doing.

— ミスティック・リバー (2003)

トムは先週ボストンで何をしてたの?

What was Tom doing in Boston last week?

何をしてたと思う?

What do you think I was doing?

先日庭で何をしてた?

What were you doing in the garden the other day?

— いまを生きる (1989)

一緒に何をしてたのかと聞かれたらどうする?

What should we do if they ask what we were doing together?

— 善き人のためのソナタ (2006)

ふたりで何をしてた?

What were you two doing?

— イル・ポスティーノ (1994)

うちの者は何をしてたんだ

What was our guy doing?

— Sanjuro (1962)

その時、何をしてたの?

What were you doing then?

父さん、何をしてたの?

Dad, what were you doing?