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 word "predator"(Para. 2)most probably means "______".
选项 A、early man
B、wild animal
C、evil person
D、campfire
答案B
解析 本题属于词汇语义题。我们知道，文章在前两段谈论的是动物的眼睛和公路反光标志牌的共同之处。据此判断，第二段第二句讨论的应是这两者的警戒作用；而既然该句前半部分说的是公路反光标志牌，那么后半部分涉及的则应是动物的眼睛。因此，在四个选项中，B)的意思最为贴切。故选B)。
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