Every means prevent the water from .
A. are used to; polluting
B. will be used to; polluting
C. is used to; polluted
D. is used to; being polluted
网友回答
A. are used to; polluting
B. will be used to; polluting
C. is used to; polluted
(答案→)D. is used to; being polluted
解析：句意：为了防止水被污染，每一种方法都被试过了。Means:方式，方法。这个单词是单复数同形，因此要由其前面的定语决定它是单数还是复数，由every可知谓语动词要用单数，故排除A。又因为water与污染pollute之间构成被动关系，排除B；再由from为介词，后要加being done才可构成被动，排除C，故答案选D。