--Why does the lake smell terrible?---Because large quantities of water .A. have pollutedB

问题补充：

--Why does the lake smell terrible?

---Because large quantities of water .

A. have polluted

B. is being polluted

C. has been polluted

D. have been polluted

答案：

A. have polluted

B. is being polluted

C. has been polluted

(答案→)D. have been polluted

解析：考查主谓一致。本题属于主谓一致里特殊用法large quantities of的后面既可以接可数名词也可以接不可数名词，谓语动词都使用复数形式。句意：—为什么这个湖闻起来很臭？—因为大量的水都已经被污染了。根据句意说明使用被动语态。而且是已经被污染了，也要使用现在完成时的形式。故D正确。