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cast-in-place
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发布时间：2022-01-07
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Television works in much the same way as radio. In radio，sound is changed into electromagnetic (invisible light) waves which are sent through the air. Experiments leading to modern television took place more than a hundred years ago. By the 1920s inventors and researchers had turned the early theories into working models.Yet it took another thirty years for TV to become an industry.
The influence of TV on the life of people is incalculable：it can influence their thoughts and their way of life. It can also add to their store of knowledge. Educational TV stations offer teaching in various subjects. Some hospitals use TV for medical students to get close-up views of operations. At first television programs were broadcast in black-and -white. With the development of science and technology，the problem of how to telecast them in full color was solved and by the middle 1960s the national networks were broadcasting most of their programs in color.
The programs that people watch are not only local and national ones. Since the launching of the first communications satellite，more and more programs are telecast "live" from all over the world. People in San Francisco were able to watch the 1964 Olympic Games in Tokyo. And live telecasts now come from outer space. In 1969，the first astronauts to land on the moon televised their historic "moon walk" to viewers on the earth. Since then，astronauts have regularly sent telecast to the earth.
56. Television is said to be the modern wonder of electronics，because _______.
A. it is an industry
B. it broadcasts most of the programs in color
C. it brings the world into people's own home in sight and sound
D. it influences people's thoughts
57. Television became an industry in _______.
A. 1920
B. 1969
C. the l920s
D. the 1950s
58. The word "incalculable" means______.
A. very great
B. uncertain
C. hard to tell
D. very small
59. The development of science and technology made it possible for television programs to _______.
A. be telecast again
B. be kept for later use
C. be put on video tape
D. be telecast in full color
60. The launching of communications satellites made it possible for people to _______.
A. get close up views of operations
B. learn various subjects
C. watch the 1964 Olympic Games in Tokyo
D. watch local programs
