In the past 50 years, there ______ a great increase in the amount of research ______on the human brain.

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问题 In the past 50 years, there ______ a great increase in the amount of research ______on the human brain.

选项 A、was. .. did
B、has been. . . to be done
C、was. .. done
D、has been. . . done

答案D

解析 本题考查是对句子时态的考查。根据句子中的时间状语:in the past 50 years,可以判断句子应该用现在完成时,而本句中表达的是已经做了的实验,应该用过去分词表示完成和被动。因此D项为本题正确答案。
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