题目内容
The retired professor, _____ in his new book in the past three years, hasn’t realized the decline in his health.
A.involved B.being involved
C.having involved D.to be involved
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题目内容
The retired professor, _____ in his new book in the past three years, hasn’t realized the decline in his health.
A.involved B.being involved
C.having involved D.to be involved