A: That a capella number you and Peter did was unbelievable.B: You think so? Well, we _______________- for such a long time. 여기서 practiced가 맞는 답인지는 알겠는데 보기 중에 did practice가 있더라고요.did practice가 왜 답이 안되는지 설명 부탁드려요.