A-A+
In the past 50 years there ______ a great inc
问题详情
In the past 50 years, there ______ a great increase in the amount of research on the human brain.
A．was.., did
B．has been.., to be done
C．was.., doing
D．has, been.., done请帮忙给出正确答案和分析，谢谢！
参考答案
正确答案：D
解析：根据inthepast50years判断，需用现在完成时；过去分词短语和不定式都能做定语，但本句想表达的是已经做了的实验，因此应用过去分词表完成和被动，选项D正确。
