题目内容
【题目】All possible means ________been taken to prevent the river________.
A. have;polluting
B. has; polluted
C. has; from polluted
D. have;being polluted
【答案】D
【解析】句意:为了防止河流被污染,所有可能的方法都采用了。主语为all possible means,谓语动词用复数;河流应是被污染,因此用被动语态。prevent. .from doing.阻止/阻挠……做……
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