Some people say radio was invented by Marconi of Italy. Marconi sent the fir

Some people say radio was invented by Marconi of Italy. Marconi sent the first radio communication(1)signals through the air in 1895. In fact, no one person can be called the(2)inventor of radio. Many people, including several Americans, helped to(3)develop radio. You may not know their names. However, their work(4)affected many people.
    Over the years, radio has become one of the most important(5)forms of communication. It can be used for two-way communication, such as between a ship and land.
    Scientists even use radio to communicate into space. And radio (7)broadcasts let people send words, music and information to any part of the world.
    The first(8)experimental radio broadcasts in the United States were made in the early nineteen hundreds.
    One of the first broadcasts came from the Metropolitan Opera House(大都会歌剧院)in New York City in 1910. It included music by the great singer Enrico Caruso. An American inventor, Lee De Forest developed some of the technology used in early radio.(9)During his lifetime, he invented hundreds of devices that were used in telephones, shortwave radio broadcasts, and similar technology.
    His most famous invention was the vacuum tube, or electron tube.(10)In 1906, the electron tube was considered the single most important development in electronics. The device made it possible to strengthen radio signals and to send them over long distances.(11)It was a major reason for the fast growth of the electronics and communications industries in the early 20th century.