24. The old building was a library, but it is empty(空的)now. The building has a long history.It______
問題詳情
24. The old building was a library, but it is empty(空的)now. The building has a long history.It__________ before my grandfather__________ born. (A) is built; be (B) has built; has been (C) had been built; was (D) is building; had been