들었을

들었을

"Had heard" (past tense form of 듣다, "to hear").

The word '들었을' is used as the past tense form of '듣다' (to hear), functioning within a time clause to set the timing of the main action, '놀랐어요' (was surprised).

나는 어제 친구의 이야기를 들었을 때 매우 놀랐어요.

I was very surprised when I heard my friend's story yesterday.

Here, '들었을 경우' introduces a conditional clause with '들었을' indicating a hypothetical past hearing scenario acting as a setup for the potential reaction

그 소식을 들었을 경우, 당신은 어떻게 하겠습니까?

If you hear the news, what would you do?

In this sentence '들었을' again reflects a past action, here specifically associated with experiencing an event, '들었을 때' (when listened to).

음악을 들었을 때 기분이 정말 좋아졌어요.

When I listened to music, my mood really improved.