In the past ten years,they _three great scientific experimeent.A finished B have finished
问题描述：
In the past ten years,they _three great scientific experimeent.A finished B have finished
C had finished D have been finished
答
B
In the past ten years是从过去到现在的一段时间,用现在完成时.
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不明白的再问哟!请记得采纳,多谢!