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不同文化的接触是人类进步的路标，在人类历史的长河中，因不同文化的交流与融合而带来文化繁荣和社会发展的事例不胜枚举。中国历史上著名的“丝绸之路”，是东西方文化交流的楷模。

我们生活在多元文化的“地球村”里。面对不同文化，青少年应如何做一名友好往来的使者？

在测量小灯泡额定电功率时，电压表出现了故障不能使用，小明向老师借了一只定值电阻R₀，设计了如图所示的电路，按下面的顺序测量额定电压为U_额的小灯泡的额定功率（R₀、U_额为已知、电流表的内阻小，可忽略不计）：

上述实验过程中涉及的三次分离操作分别是（   ）