问题
选择题
------ Why does the lake smell terrible?
------ Because large quantities of water _________.
A．have been polluted
B．has polluted
C．have polluted
D．has been polluted
答案
答案：A
考查主谓一致与语态。large quantities of +名词作主语，位于动词用复数；water与pollute构成被动的关系。所以选择A。