---Whydoesthelakesmellterrible?---Becauselargequantitie...

问题详情：

--- Why does the lake smell terrible?

---Because large quantities of water        .

A．have polluted                                      B．is being polluted

C．have been polluted                                  D．has been polluted

【回答】

C

知识点：动词时态与语态

题型：选择题