It was not until all the fish died in the riverthe villagers realized the serious pollutio

问题补充：

It was not until all the fish died in the riverthe villagers realized the serious pollution.

A. where

B. that

C. what

D. which

答案：

A. where

(答案→)B. that

C. what

D. which

解析：考察强调句型。强调句型的基本结构：it is/was 被强调成分that/who其他成分。去掉it is/was that/who句子仍然成立。本题强调的是not until all the fish died in the river.句意：直到河里的鱼都死了，村民们才意识到污染是多么的严重。