Scientists can’t yet make an invisibility cloak1 like the one that Harry Potter2 uses.But，for the first time，they’ve constructed a simple cloaking device that makes itself and somethingplaced inside it invisible to microwaves.
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 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 objectcasts no shadow.Otherwise，the absence of reflected light on one side would give the obiectaway.
Invisibility isn’t possible yet with waves of light that the human eye can see.But it is nowpossible with microwaves.Like visible light，microwaves are a form of radiant energy.Theyare part of the electromagnetic spectrum，which also includes radio waves，infrared light，ultraviolet rays，X rays，and gamma rays.The wavelengths of microwaves are shorter thanthose of radio waves but longer than those of visible light.
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.
To a detector set up to receive microwaves on the other side of the ring，it looks as if thewaves 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 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 Potter’s invisibility cloak doesn’t have any real competition yet.
词汇：
invisibility/invizE5biliti/n.看不见，无形 spectrum/5spektrEm/n.光谱
cloak/klEuk/斗篷，披风 infrared/5infrE5red/adj.红外线的
microwave/5maikrEuweiv/n.微波 ultraviolet ray 紫外线
reconstruct/5ri:kEn5strQkt/v.重建 gamma ray 伽马射线
radiant/5reidjEnt/adj.辐射的 wavelength/5weivleNW/n.波长
electromagnetic/IlektrEJ5mA^nItIk/adj.电磁的coaster/5kEustE(r)/n.托盘，垫子
练习：
1.Harry Potter is mentioned in the passage，because scientists
Acan now make an invisible cloak of the same kind as he uses.
Btry to 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.
Dknow that it is possible to make an invisible cloak of the same kind.
2.What is true of microwaves?
ATheir wavelengths are shorter than those of visible light.
BTheir wavelengths are longer than those of visible light.
CThey are different from visible light as they are a kind of radiant energy.
DThey are visible to the human eye.
3.What is NOT true of the invisibility device?
AIt is made of a special material with unusual ability.
BMicrowaves bounce off it when they strike it.
CMicrowaves pass through it when they strike it.
DIt bends the microwaves all the way around until they reach the opposite
side.
4.What does the word “coaster” mean in the passage?
AA disk or plate placed under a drinking glass to protect a table top.
BA vessel engaged in coastal trade.
CA roller coaster.
DA resident of a coastal area.
5.Harry Potter’s invisibility cloak doesn’t have any real competition yet，
because
Ascientists have not found out how his cloak works.
Bthe cloaking device is a total failure.
Cthe cloaking device works only for microwaves.
Dthe cloaking device works only for visible light.
答案与题解：
1.C文章的第一段告诉我们，科学家还没有发明哈里·波特使用的那种隐身衣，所以不能选 A;该段还告诉我们，科学家已制造了，一种装置，这种装置能使自身或置于其中的物体不被微波发现，所以C是正确选择，也就是说，科学家发明的隐形装置和哈里波特的隐身衣仅仅在概念上相同，这同时说明B和D是错误的选择。
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。
3.B第四段第三句说，当微波到达装置表面时，very few bounce off。very few是几乎没有的意思，所以选择B。其他选择所述内容都可以很容易在该段中找到。
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。
5.CA句在短文中没有提到;按文章的内容B不是正确的说法;文章最后一段说，And thedevice works only for microwaves，not forvisible light，所以C是正确选择。