在方框内选择合适的句子，补全对话。

A. What's in your pencil box? B. It's purple. C. What colour is it? D. Thank you so much. E. Is this your pencil box? F. Excuse me.

— I lost my pencil box.

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— OK. Here are three purple pencil boxes.

— An eraser, two pencils, a pen, a ruler and a knife.

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— Yes, it is.

— Here you are.

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