【题目】—Do you know why the chemical plant wasn't built here?
—Because it ________ too much pollution to the air.
A.had caused
B.caused
C.will have caused
D.would have caused

【答案】D
【解析】考查虚拟语气。句意：——你知道为什么这里没有化工厂吗? ——因为（如果建了化工厂）它对空气污染太严重。此处省略了从句，表示与现在事实相反，主句用would have+过去分词，故选D。