ㄴ데 그러다

but then what happens?

-ㄴ데 lays out a situation and 그러면 asks what follows from it: I'm a senior too, so where does that leave me? It only contains one percent, so doesn't that mean there is none? 그러다 stands in for whatever was just described, so it never has to be repeated. Six of these eight lines are that 그러면 asking the consequence.

Register: casual spoken