2. 考研
  3. The (1)_____ of the fluorescent tube (2)_____ a major revolution in the development of better and cheaper lighting. First shown

The (1)_____ of the fluorescent tube (2)_____ a major revolution in the development of better and cheaper lighting. First shown

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问题     The (1)_____ of the fluorescent tube (2)_____ a major revolution in the development of better and cheaper lighting. First shown at the New York and San Francisco World (3)_____ in 1939, this more efficient, more diffuse, longer-lived lamp has been (4)_____ improved, so that slowly it (5)_____ the supremacy of the incandescent household globe. The fluorescent tube (6)_____ Australian homes, shops and factories today is seven or eight times (7)_____ the tubes that brought shadow-free lighting to many of Britain’s wartime factories. Its (8)_____ too, is much greater—from 2,000 hours in 1940 to mc/re than 7, 500 hours today.
    But (9)_____ its (10)_____ use for more than 30 years, the fluorescent tube remains a
(11)_____ to many of its users. It is built (12)_____ a completely different (13)_____ from the incandescent light. In the incandescent bulb, a tungsten wire (14)_____ than a human hair, is brought to white-hot temperature by passing an electric (15)_____ through it. In the fluorescent tube a stream of electrons bombards a gas containing mercury, (16)_____ invisible ultraviolet radiation. The ultraviolet rays hit the fluorescent coating that (17)_____ the tube, (18)_____ it to grow. A 40 watt fluorescent tube gives twice as much light as a 100.watt tungsten globe, (19)_____ about five times as long, and runs cool enough to (20)_____ higher levels of light.

选项 A、lifeline
B、lifework
C、lifespan
D、lifeguard
答案C
解析 lifespan意为"寿命"，符合题意。1ifeline"生命线"；1ifework"毕生事业"；lifeguard"救生员"。
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