| 摘要 |
A reusable bingo card comprising an exposed microporous layer having bingo numbers permanently imprinted thereon, and a liquid impervious support sheet bonded to the exposed layer. The support sheet is substantially darker than the background area of the exposed layer. To mark a number on the card a colorless volatile liquid is applied to the exposed layer making the applied area transparent and exposing the support sheet below producing a contrasting indicia that is darker than the background area but lighter than the numbers. Evaporation of the marking liquid restores the bingo card to its original appearance for reuse.
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