Question

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

Answer 1

答案：
解析：

这是一个倒装句，以not until开头的句子要用倒装结构，因为这个句子是一般过去时，所以在主语前要加did，谓语动词用原形。