填空题 The word laser stands for "light amplification by stimulated emission of radiation". To many people lasers are very{{U}} (36) {{/U}}, but a laser is simply a{{U}} (37) {{/U}}that produces a very strong light. The light from a laser is called{{U}} (38) {{/U}}light because it is light that moves in only one direction. In contrast, incoherent light, like the light form the sun or a light{{U}} (39) {{/U}}, moves away from its{{U}} (40) {{/U}}in all directions and{{U}} (41) {{/U}}in a narrow beam. As soon as the laser was developed, scientists began thinking of practical{{U}} (42) {{/U}}for it. One of the earliest uses was to make extremely{{U}} (43) {{/U}}measurements of distance and speed. As time passed, many more applications for the laser were developed.{{U}} (44) {{/U}}.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,{{U}} (45) {{/U}}One such fiber can carry more than a million conversations at the same time! {{U}} (46) {{/U}}.