Invisibility Ring
When a person sees an object，his or her eye senses many different waves of visiblelight as they bounce off the object.The eye and brain then work together to organize thesesensations and reconstruct the objects original shape. So，to make an object invisible，scientists have to keep waves from bouncing off it.And they have to make sure the objectcasts no shadow.Otherwise，the absence of reflected light on one side would give the obiectaway.
The scientists new invisibility device is the size of a drink coaster and shaped like aring.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 allthe way around until they reach the opposite side.The waves then return to their originalpaths.
When the researchers put a small cdpper loop inside the ring，it，too，is nearly invisible. However，the cloaking device and anything inside it do cast a pale shadow.And the deviceworks only for microwaves，not for visible light or any kind of electromagnetic radiation.So，Harry Potters invisibility cloak doesnt have any real competition yet.
invisibilityn.看不见，无形 spectrumn.光谱
microwaven.微波 ultraviolet ray 紫外线5ri:kEn5strQktp
radiantadj.辐射的 wavelengthn.波长
练习：
Acan now make an invisible cloak of the same kind as he uses.
Ctry to invent a device Similar in idea to the invisible cloak he uses.
2.What is true of microwaves?
BTheir wavelengths are longer than those of visible light.
DThey are visible to the human eye.
AIt is made of a special material with unusual ability.
CMicrowaves pass through it when they strike it.
side.
AA disk or plate placed under a drinking glass to protect a table top.
CA roller coaster.
5.Harry Potters invisibility cloak doesnt have any real competition yet，
Ascientists have not found out how his cloak works.
Cthe cloaking device works only for microwaves.
答案与题解：
2.B第三段最后一句中告诉我们，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，不能选择;根据该段第一句：with wavesof light that the human eye can see和第三句：Like visible light，可以得知D是错误的说法，也不能选择。
4.A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是正确选择。coaster是一个多义词，其他几个选择是该词的其他意思，B：从事沿海贸易的船;C：过山车，摩天轮;D：海岸地区居民。