/kloc-In the middle of 0/9th century, there were no electric lights in the world. At night, people can only explore life by candlelight or in the dark. Once, Edison read in a magazine: Yes, Americans invented the carbon filament electric lamp. He thought this kind of electric lamp was too short and impractical, so he made up his mind to develop it himself. He began to look up information, write notes and do experiments, and put a lot of energy into it. He and his assistants experimented with more than 7000 kinds of heat-resistant materials, and it took about thirteen years to finally make a practical incandescent lamp.
So that the electric light really entered thousands of households and brought light to people.