Can you Name This Korean Song?

When I was at a Korean Resturant the other day, an awesome song came on. It sounded almost like it could be an anime opening(even if I doubt it was). I tryed to hear what she was saying, but it was kind of hard to tell in the loud resturant, so I can't really tell you much about it. She sang aaa alot. When she sang the chorus it sounded like she said the same thing twice, but when you listened closer it was two different phrases. I'm not really sure if anyone can tell what song it is from that, but if you could even tell me about some famous Korean songs it would help!

Thank you~