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】______.
【B5】
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