问题补充:
Not until all the fish died in the river how serious the pollution was.
A. did the villagers realize
B. the villagers realized
C. the villagers did realize
D. didn’t the villagers realize
答案:
(答案→)A. did the villagers realize
B. the villagers realized
C. the villagers did realize
D. didn’t the villagers realize
解析:
A。以not until开头的句子,主句要用部分倒装。