2. 外语
  3. The word laser stands for "light amplification by stimulated emission of radiation". To many people lasers are very【B1】______, b

The word laser stands for "light amplification by stimulated emission of radiation". To many people lasers are very【B1】______, b

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问题     The word laser stands for "light amplification by stimulated emission of radiation". To many people lasers are very【B1】______, but a laser is simply a【B2】______that produces a very strong light. The light from a laser is called【B3】______light because it is light that moves in only one direction. In contrast, incoherent light, like the light form the sun or a light【B4】______, moves away from its【B5】______in all directions and【B6】______in a narrow beam.
    As soon as the laser was developed, scientists began thinking of practical【B7】______for it. One of the earliest uses was to make extremely【B8】______measurements of distance and speed. As time passed, many more applications for the laser were developed.【B9】______.From laser printers to technology by which whole encyclopedias of information can be stored on a laser disk (called a CD-ROM) and read by a computer, lasers are revolutionizing computers.
    Lasers have also made a big difference in the way telephones work. Instead of changing sound waves to electricity that travels through copper wire,【B10】______One such fiber can carry more than a million conversations at the same time!
  【B11】______.
【B9】
选项
答案Over the past twenty years, personal computers have brought tremendous’ changes to the home and the workplace. And many of the most important developments in computer technology are based on lasers.
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