票를 預買해야 하지?
票를 豫買해야 하지? 預 means to entrust, 豫 in advance.
I put "we have to book our tickets, right" and it was marked as wrong - a lot is often assumed in Korean without it having to be said outloud :/
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Yes indeed. A wider range of correct responses would help. the "Ji" at the end indicates a tag question. Still, I missed it, leaving off the English equivalent "right?" 표를 예매해야 하지?
'You have to reserve tickets, right?' should be accepted