◎ 题干
_____ such heavy pollution already, it may now be too late to clean up the river.

 [     ]

A. Having suffered
B. Suffering
C. To suffer
D. Suffered
◎ 答案
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◎ 解析
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◎ 知识点
    根据魔方格专家分析,试题“_____ such heavy pollution already, it may now be too late to clean up the river. [ ]A. Having suffered B. SufferingC. To suffer D. Suffered …”主要考查了你对  【现在分词的完成式】  等知识点的理解和应用能力。关于这些知识点的“档案”,你可以点击相应的链接进行查看和学习。