You didn't know enough people. You ___ join a club and make friends.

Historian J. H. Plumbs remarks are cited to show thatA．adults and children had many things in common.B．adults and children enjoyed a pretty close relationship.C．both childhood and adulthood are new topics.D．adulthood is not a historic and natural fact 点击查看答案

下图的输入电阻为()。

A.3.2KΩ
B.1.6KΩ
C.2.4KΩ
D.1.8KΩ

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