사실 이 문장에서는 know와 think 모두 적절한 단어랍니다! 그러므로 취향껏 골라서 쓰셔도 상관없답니다.
Ex: I didn't think the store would close so early. We came for nothing!
= I didn't know the store would close so early. We came for nothing! (가게가 이렇게 일찍 닫을 줄 몰랐네. 괜히 헛걸음질만 했네!)