两句话翻译obsidianisablack,volcanic,w

两句话翻译obsidianisablack,volcanic,w: obsin is a black,volcanic, well, almost like glass. It flakes very nicely into really sharp points. You can still see the diagonal marks of the ladders in the plaster on the inside walls.; 黑曜石是一种类似玻璃的黑色火山石，它断片的边缘很锋利。（石器时代的人用来作为砍削的工具）仍然可以看到内墙的灰泥上留下的斜搭梯子的痕迹。