New ways have been found to prevent the river .
A. not to be polluted
B. against polluting
C. from polluting
D. from being polluted
网友回答
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。