았/었더라면 [Intermediate Grammar]

  - 았/었더라면

It is added to a stem of a verb or an adjective supposing the fact has been done in the past would be in a different situation.

Example: 

1. 조금만 조심했더라면 사고가 나지 않았을 텐데..
    If I were more careful, I wouldn't have had an accident.

2. 현금으로 가지고 갔더라면 문제가 없었을 거예요.

    If I had cash, I wouldn't have had a problem.

3. 그 사람이 도와주지 않았더라면 굉장히 고생했을 거예요.
    If he didn't help me, I would've gotten in big trouble.

4. 오늘 생일인 줄 알았더라면 작은 선물이라도 준비했을 텐데...

    If I had known it was your birthday today, I would have prepared a small present...

5. 아침에 일기 예보를 들었더라면 우산을 가지고 왔을 거예요.

If I had listened to the weather forecast in the morning, I would have brought an umbrella.