来源：学生作业帮 编辑：作业帮 分类：英语作业 时间：2024/05/24 03:03:48
高一英语选择题 需要理由
It's said that one kind of time machine _____ by a sceientist ,with which man can travel wherever he would like.
A.had been invented B.has been invented
C.had been dicovered D.has discovered
选B.现在完成时的被动语态：have/has been done
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