－Why does the river smell terrible?－Because large quantities of waterA. have been pollute

问题补充：

－Why does the river smell terrible?

－Because large quantities of water．

A. have been polluted

B. is being polluted

C. has been polluted

D. have polluted

答案：

(答案→)A. have been polluted

B. is being polluted

C. has been polluted

D. have polluted

解析：“受到污染”即“被污染”应该用被动语态，故排除D选项。“河水被污染”已经造成后果，故用现在完成时，所以排除B选项。large quantities of water中是large quantities作主语，故谓语动词用复数形式。选项A 正确。句意：——这条河的河水为什么发臭啊？——因为大量的河水被污染了。