Television broadcasts are 【C1】______ to an area that is within the 【C2】______ of the sending station or its relay (中转站)．【C3】______ television relays are often placed on hills and mountains so that they can 【C4】______ a wider region, they still can not cover more land than one from the hilltop 【C5】______ a clear day.
However, the rays also go out into the atmosphere, 【C6】______ there is a relay station on a satellite that 【C7】______ around the earth, it can send the pictures to any point on the earth from which the satellite is 【C8】______ ．Three satellites 【C9】______ turning around over the equator (赤道) send any television program to any part of the earth．【C10】______ makes it possible for world 【C11】______ of newspapers to give the news in all countries at the same time．【C12】______ it may be possible for a subscriber (户) to a televised newspaper to 【C13】______ a button and see a newspaper page 【C14】______ his television screen．He could also decide when he wants the page 【C15】______ , 【C16】______ , by dialing different numbers such as 【C17】______ on a telephone dial, he could choose the language or the edition of the paper he wants to read.
It seems strange to think that, even today, methods of the 【C18】______ are not entirely useless．For example, sometimes 【C19】______ agencies which use radio also use pigeons to 【C20】______ messages between offices in large cities because the pigeons are not bothered by traffic problems.
【C1】______