The water will be polluted unless some measures .
A. will be taken
B. are being taken
C. are taken
D. were taken
网友回答
A. will be taken
B. are being taken
(答案→)C. are taken
D. were taken
解析：考察时态及语态。句意：除非采取了一些措施，否则这些水会被污染。句子描述的是一个过去的动作，故用过去时态，measures是take的动作对象，故用被动语态，选D。