Not until the press reported the pollution why the water supply had been cut off.
A. people did know
B. people had known
C. did people know
D. had people known
网友回答
A. people did know
B. people had known
(答案→)C. did people know
D. had people known
解析：not until 位于句首，句子使用部分倒装。排除ＡＢ，Ｄ答案时态不对。句意：
直到新闻报道了污染人们才知道为什么水的供应被切断。