of the water polluted. We must try to protect our environment.A. Two third; areB. Two th

问题补充：

of the water polluted. We must try to protect our environment.

A. Two third; are

B. Two third; is

C. Two thirds; are

D. Two thirds; is

答案：

A. Two third; are

B. Two third; is

C. Two thirds; are

(答案→)D. Two thirds; is

解析：句意：三分之二的水被污染了。我们必须保护我们的环境。在英语中分子用基数词表达，分母用序数词表达如果分子大于1，分母变复数。分数作主语时，根据其后接的词而定，如果为不可数名词，则相当于单数，如果其后接的为可数名词复数形式，则相当于复数。根据句意，故选D。