2. 外语
  3. What do cats’ eyes and highway reflector signs have in common? They both act as retro-reflectors(反响反射器). Almost everyone has

What do cats’ eyes and highway reflector signs have in common? They both act as retro-reflectors(反响反射器). Almost everyone has

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问题     What do cats’ eyes and highway reflector signs have in common? They both act as retro-reflectors(反响反射器).
    Almost everyone has noticed the frightening appearance of animals at night, as their eyes seem to glow in reflected light. One may think that just as reflective highway signs alert the motorists to many road hazards, so early man was often warned of danger by light from his campfire reflected in the eyes of lurking(潜伏)predators. In both cases, the light is ret-roreflected, giving it a particularly bright appearance.
    The principles of retroreflection have been understood for centuries. However, it is only within the last fifty or sixty years, with the wide use of the automobile, that this area of optics(光学)has received important commercial application. Today, the uses of retroreflective materials are many. They are applied to bicycles and motor vehicles to make them more visible at night. And they assist pilots by improving the visibility of runway markers.
    Large sums are spent for retroreflective materials, but purchasers have often found it difficult to specify performance for the materials they buy. Performance is of concern not only from the standpoint of the brightness of reflected light, but also from the standpoint of its color. It is important, for example, that the yellow hues(色调)in warning signals be of consistent color quality on all road signs so the driver can rely on color, as well as shape, to discern the signs’ meanings. Seven colors — silver, blue, yellow, red, green, brown and orange — are currently used for marking the interstate highway system.
The passage suggests that______.
选项 A、government scientists are developing inexpensive retroreflectors
B、the government manufactures retroreflective devices
C、retroreflective devices are widely used for public facilities
D、retroreflectors were first used to scare wild animals away
答案C
解析 本题属于推理判断题。文章提到，机场跑道指向标(第三段最后一句)、道路标志牌(第四段第三句)、州际公路系统(第四段最后一句)等均采用了反向反射材料。可见，反向反射装置被广泛地应用于公共设施。所以选项C)为正确答案。
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