I'm having trouble making sense of the sentence below. (It's taken from 『いつかこの恋を思い出してきっと泣いてしまう』.) I would appreciate anyone's help.
The subjects are left out...
"If you could have taken a day off (today), I would have taken a paid holiday, too... (so that we could stay together one more day...)"
有給 is short for 有給休暇 "paid leave from work".
The author is complaining that even though he was able to take a paid leave, he is going to spend it in a crowded, packed subway train.
The rest of the conditional is left implicit:
If you are able to take a vacation (you should spend it in a nice place)