5分钟左右的演讲
英语的 好的话加分
5分钟左右的演讲
英语的 好的话加分
The telephone is a telecommunications device that transmits and receives sound, most commonly the human voice. It is one of the most common household appliances in the developed world, and has long been considered indispensable to business, industry and government. The word "telephone" has been adapted to many languages and is widely recognized around the world.
The device operates principally by converting sound waves into electrical signals, and electrical signals into sound waves. Such signals when conveyed through telephone networks — and often converted to electronic and/or optical signals — enable nearly every telephone user to communicate with nearly every other worldwide.Alexander Graham Bell borned in March 3, 1847, And he died in August 2, 1922. He was an eminent scientist, inventor, engineer and innovator who is credited with inventing the first practical telephone.
Bell's father, grandfather, and brother had all been associated with work on elocution and speech, and both his mother and wife were deaf, profoundly influencing Bell's life's work. His research on hearing and speech further led him to experiment with hearing devices which eventually culminated in Bell being awarded the first U.S. patent for the telephone in 1876. In retrospect, Bell considered his most famous invention an intrusion on his real work as a scientist and refused to have a telephone in his study.