重点句型运用 — 英语选择题

根据“以前学校没有食堂，现在有一个食堂”选择正确表达。A. There was a dining hall before, but now there is no one. B. There was no dining hall before, but now there is one. C. There is no dining hall before, but now there was one. D. There were no dining hall before, but now there is one.