으면

If; also, I wish

The basic if or when. What stands out in these lines is that almost all of them stop dead right after it and leave the result unsaid, which is a way of making the hope or the fear hang in the air: if we can just find cheap petrol today. On a past-tense stem that trailing use becomes a wish, which is what the line hoping to pass the exam does; written in full it would end with 좋겠다.

Register: everyday; the trailing use is spoken and caption style