问题
选择题
—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
答案：D
考查主谓一致及时态。large quantities of +不可数名词，谓语动词用单数，根据句意用现在完成时。句意：——为什么这湖这么难闻？——因为大量的水已经被污染了。