It's up in the air.
아직 확실하지 않아요

May: John， how's your new class going?
John: Okay， I guess.
May: Just okay? You don't sound very excited about it. What's up?
John: Oh， it's just a bit different from what I expected. I expected something I could use in actual situations as soon as I graduate. But it's all about economic theories.
May: Well， maybe those theories will turn out to be practical after all. You haven't started your real career yet.
John: You're right. Maybe I'm impatient. It seems like I'm wasting my time， that's all.
May: What do you really want to do after you graduate?
John: To tell the truth， I'm not even sure what I really want. It's still up in the air.

* theory: 이론
ex) Eistein's theory of relativity (아인쉬타인의 상대성 이론)
* turn out to be: ~이 되다， ~인 것으로 드러나다
* career: 경력
* impatient: 참을성이 없는， 조급한.