And the image on the top left is a copper sheet.

左上角的图像是铜板。

Sheet copper is much used for covering the bottoms of ships, and for making kettles and saucepans and many other household articles.

铜片可以用于覆盖船底以及制造水壶、炖锅与其他居家物品。

But if we heat a piece of sheet copper in a clear fire, we shall find that the surface turns black, from the copper rust which forms all over it.

然而，如果我们使用明火对铜片进行加热，那么就会发现其表面从铜锈处开始变黑。