一道简单高中英语题（请进！请详细说明！谢谢！）

Question

Researchers are trying to find out , if possible , _______ caused the pollution of
the water in that area.
A what was it that B it was that what
C it was what that D what it was that

Answer 1

答案：D.

翻译：研究人员正在尽力找出（如果可能找出的话）是什么导致了那片地区水污染。

解释：
1. 此题find out后面是一个宾语从句。
该宾语从句含有一个if possible的条件状语从句，而其主句则是强调句型的特殊疑问句结构。
2. 该宾语从句分析推理如下（抛开状语从句if possible）：
(Waste water from factories) caused the pollution of the water in that area.
如果对该句主语Waste water from factories进行强调，则该强调句为：
It was waste water from factories that caused the pollution of the water in that area.
该强调句的特殊疑问句（即对被强调部分Waste water from factories进行划线提问）为：
What was it that caused the pollution of the water in that area?
3. 上句如果做为（题中find out的）宾语从句，则变成“引导词 + 陈述句”结构，即为：
what it was that caused the pollution of the water in that area
即为答案D。

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参考资料：英语牛人团

Answer 2

D。 find out后面接宾语从句，所以后面是陈述句,陈述句中有强调句what it was....that....