【题目】The government has taken some measures to reconstruct the earthquake-hit areas， but it must be some time _______ everything returns to normal.
A. sinceB. after
C. unlessD. before
在线课程【答案】D
【解析】
考查固定结构。It+be +some time+before….要过一段时间才。。。。句意：政府已经采取措施重建地震灾区，但是必须要过一段时间一切才能恢复正常。选D。