跟踪导练(三)

• 来源期刊: 时代英语：高二版
• 学科: 教育
• 年，卷（期）: sdyygeb_2017,（5）
• 页码范围: 48-50
• 页数: 3页
• 分类号: G634.41

摘要

<正>阅读地带A Today I’ll be talking about the invention of the camera and photography.The camera is often thought to be a modern invention,but as early as 1727,a German physicist discovered that light darkens silver salt.Used as a camera,a big box was set up,and a small hole was cut in one side to let the light in;he made temporary pictures on the salt.Silver salt is still the base of the photographic film today.Then a French scientist made the first permanent picture by using a