Our government has taken some measures to overe the lack of electricity, but it may take some time we have enough power．
A. since
B. after
C. unless
D. before
网友回答
A. since
B. after
C. unless
(答案→)D. before
解析：考查固定结构。“It be+一段时间+before 从句”表示“一段时间以后某事才发生”，结合句意可知D正确。句意：我们的政府已经采取了一些措施来克服电力紧缺的问题，但是也许要一段时间以后我们才会有足够的电力。