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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

题目详情
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
▼优质解答
答案和解析
选B.现在完成时的被动语态:have/has been done