Our waste recycling project a lot of investigation and paperwork had been done by the en

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A. involved
B. to involve
C. being involved
(答案→)D. involving
解析：答案：D　考查非谓语动词。句意为：我们的废物回收利用工程包括很多调查和文书工作已经在上学期末完成了。involve“包含，包括”，与主语“project”是主动关系，所以用现在分词involving作定语。故答案选D。