어찌나 + A/V + 는지 is used to emphasise the character of something and your reaction to it – ‘it’s soooo A/V that…’:
밤에 배구 한 후에 저는 어찌나 피곤했는지 집에 가서 바로 잠이 들었어요.
Last night after volleyball I was so tired that I went home and immediately fell asleep.
저는 친구의 불평에 어찌나 질렸는지 제가 그에게 나가라고 했어요.
I was so fed up of my friend’s complaints that I asked him to leave.
그 남자가 저에게 전화를 어찌나 자주 하는지 귀찮아 죽겠어요.
That guy calls me so often that it annoys me to death.
두 사람은 어찌나 많이 닮았는지 모두 형제인줄 알아요.
Those two resemble each other so much that everyone thinks they’re siblings.
Usain Bolt는 어찌나 빠른지 그를 따라올 사람은 없었어요.
Usain Bolt is so fast that no one else can match him.
여름에 날씨가 어찌나 더웠는지 샤워를 세 번씩 했어요.
In the summer the weather was so hot that I had to shower three times a day.
저는어찌나 당황스러웠는지 죽겠어요!
I was so embarrassed that I wanted to die!