New ways have been found to prevent the river .A. not to be pollutedB. against pollutingC.

问题补充：

New ways have been found to prevent the river .

A. not to be polluted

B. against polluting

C. from polluting

D. from being polluted

答案：

A. not to be polluted

B. against polluting

C. from polluting

(答案→)D. from being polluted

解析：固定词组。Prevent sb (from) doing sth阻止某人做某事；句意：新的方法已经被发现来阻止河流被污染。