Riddle #133

Question: There are three boxes labeled "Apples", "Oranges", and "Apples and oranges". Each box has the wrong label on it. How could you correctly label all three of the boxes by taking only one piece of fruit fruit from one of the boxes?

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Question: What can be broken but never forgotten?

Question: People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?