Much has been done to keep the air .A.from pollutingB.from being pollutedC.pollu
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Much has been done to keep the air ________.
A.from polluting
B.from being polluted
C.polluting
D.being polluted
试题答案
B
【巧解导析】“the air”与“pollute”的关系为被动关系，排除A，C项；而D项的含义与句意不符合．Keep表示“阻止”的含义时，其后的from不能省略．