(二)InvisibilityRing根据以下材料，回答问题。Scientistscan'tyetmakeaninvisibilitycloa

共享题干题 (二)Invisibility Ring根据以下材料，回答问题。 Scientists can't yet make an invisibility cloak like the one that Harry Potter uses. But, for the first time, they've constructed a simple cloaking device that makes itself and something placed inside it invisible to microwaves. When a person "sees" an object, his or her eye senses many different waves of visible light as they bounce off the object. The eye and brain then work together to organize the sensations and reconstruct the object's original shape. So, to make an object invisible, scientists have to keep waves from bouncing off it. And they have to make sure the object casts no shadow. Otherwise, the absence of reflected light on one side would give the object away. Invisibility isn't possible yet with waves of light that the human eye can see. But it is now possible with microwaves. Like visible light, microwaves are a form of radiant energy. They are part of the electromagnetic spectrum, which also includes radio waves, infrared light, ultravioletmys, X rays, and gamma rays. The wave lengths of microwaves are shorter than those of radio waves but longer than those of visible light. The scientists' new "invisibility device" is the size of a drink coaster and shaped likearing. The ring is made of a special material with unusual ability. When microwaves strike thering, very few bounce off it. Instead, they pass through the ring, which bends the waves all the way around until they reach the opposite side. The waves then return to their original paths. To a detector set up to receive microwaves on the other side of the ring, it looks as if the waves never changed their paths as if there were no object in the way! So, the ring is effectively invisible. When the researchers put a small copper loop inside the ring, it, too, is nearly invisible.However, the cloaking device and anything inside it do cast a pale shadow. And the device works only for microwaves, not for visible light or any kind of electromagnetic radiation. So, Harry Potter's invisibility cloak doesn't have any real competition yet.1.[不定向选择题]What does the word "coaster" mean in the passage?A.A disk or plate placed under a drinking glass to protect a table top. B.A vessel engaged in coastal trade. C.A roller coaster. D.A resident of a coastal area. 2.[不定向选择题]What is true of microwaves?A.Their wavelengths are shorter than those of visible light B.Their wavelengths are longer than those of visible light. C.They are different from visible light as they are a kind of radiant energy. D.They are visible to the human eye.

1.参考答案：A
参考解析：第四段第一句告诉我们，科学家的这个隐形装置和一个杯垫差不多大小，所以A是正确选项。coaster是一个多义词，其他几个选项是该词的其他意思，B项意为“从事沿海贸易的船”；C项意为“过山车，摩天轮”；D项意为“海岸地区居民”。
2.参考答案：B
参考解析：第三段最后一句告诉我们，A是错误选择，B是正确选择。该段第三句说，微波与可见光一样都是一种辐射能，所以C的说法是错误的，不能选；根据该段第一句：with wavesof light that the human eye can see和第三旬：like visible light，可以得知D是错误的说法，也不能选。3.[不定向选择题]Harry Potter's invisibility cloak doesn't have any real competition yet, because __________.A.cientists have not found out how his cloak works. B.the cloaking device is a total failure. C.the cloaking device works only for microwaves. D.the cloaking device works only for visible light.

感谢回答，我学习了