题目内容
【题目】In the 1950s in the USA, most families had just one phone at home, and wireless phones _______ yet.
A.haven't invented
B.haven't been invented
C.hadn't invented
D.hadn't been invented
【答案】D
【解析】二十世纪五十年代在美国,绝大多数家庭只有一部电话,无绳电话还没有发明出来.句中invent与主语phones构成动宾关系,要用被动语态;invent的动作发生在谓语动词had之前,是过去的过去,要用过去完成时态的被动语态.故选D.
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