第73课 玻璃窗

　　If you had lived in Britain a thousand years ago, you might have seen panes of glass in the churches, but you would have found very few glass windows in the houses of the people. The windows in those days were generally narrow open slits in the wall, though sometimes they were filled up with thin pieces of horn, or with thin skin.

　　穿越时空, 回到一千年前的英国, 就会发现, 只有教堂可能会使用窗格玻璃, 而平常人家几乎很少有人使用玻璃窗户。那时候的窗户实际上就是墙面上的一个狭窄开口而已, 有时候装上牛羊角的薄层或者轻薄的兽皮。

　　What a difference glass windows have made in the brightness and comfort of our homes! The glass is so transparent that it lets the light from the sun pass through it, and yet it keeps out both the rain and the wind.

　　玻璃窗改变了我们的家庭生活, 带来了不同凡响的明亮与舒适感受！玻璃的透明度极高, 可以允许阳光轻松穿过, 将风雨阻隔在外。

　　Glass is so hard that you cannot cut it or even scratch it with a common steel knife. The beautiful gem called the diamond is, however, even harder than glass; and glaziersuse small diamonds set in a handle to cut glass to the size that they want. Little wheels of extremely hard steel are also used for cutting glass, and this they do fairly well, though not nearly so well as diamonds.

　　玻璃的硬度很高, 普通的钢制刀具无法对它进行切割, 甚至都不能在它的表面留下划痕。然而, 那种被称作金刚石的美丽宝石比玻璃更加坚硬；玻璃工人使用一把带有手柄的金刚石切割工具将玻璃切割为需要的大小。人们还使用极为坚硬的钢轮对玻璃进行切割, 这种方法虽然比不上使用金刚石那样理想, 但效果还算不错。

　　If you hold a pane of thin glass under water, you will find that you can cut it with a pair of scissors. But you must cut near the edge of the glass, and take off only a little bit at a time. Like many other hard substances, glass is very brittle—that is, it will snap easily if we try to bend it, or if we let it fall.

　　如果你将很薄的一片玻璃放在水中, 就可以用剪刀来进行切割。不过你只能从玻璃的边缘入手, 而且一次只能剪下一点点。与其他坚硬的物质一样, 玻璃非常脆弱——也就是说, 如果你想要弯折它, 或者将它从高处丢下, 它就会破裂为碎片。