其他检测方法下变得部分不可见。正是这种反射吸收原理使飞机“隐身”了。大多数传统型战机都是圆形的，从而为雷达提供了一个非常有效的反射区。雷达信号接触到飞机的任何部位，都会有部分被反射回来。然而，隐形战机表面十分平整，边缘也很锋利，这样一来当雷达信号接触机身时，将会成一定角度反射散去。同时，经过加工处理的隐形战机表面还可以吸收雷达信号。结果是，像美国F-117A一类的隐形战机的雷达反射信号出仅仅如一只小鸟，而并非一架飞机。但隐形技术并不能使得飞机完全隐身。这就如同士兵们在丛林战争中使用的伪装术一样。除非士兵靠近你，不然你不会看到他。
1. The North American International Auto Show has traditionally served as an
extravagant unveiling of the latest in the automotive industry.
2. A new international initiative to increase grain crop yields could help raise
incomes for six million farmers in South Asia and combat hunger in one of the poorest regions of the world.
The U.S. space agency, NASA, is celebrating the 40th anniversary of the Apollo 8 space mission.
At NASA, 2008 will be remembered for shuttle missions, discoveries on Mars, and mysteries revealed across the solar system and beyond.
Three main Internet cables from Italy to North Africa were inexplicably severed in the second such incident in a year, plunging Egypt and several other Arab countries into a communications crisis.
Clean energies are forms of energy which do not pollute the air, the ground, or the
3. 4. 5.
6.
sea. Clean energies include:
Solar power Wind power Wave power
Salinity gradient power Tidal power Geothermal power
7. Solar power describes a number of methods of harnessing energy from the light
of the Sun.
8. The world seems increasingly divided into those who favor genetically modified
(GM) foods and those who fear them.
9. computer makers are pushing the limits of weight and power. 10. Meanwhile, labs are testing new battery technologies.
11. One of the most promising new technologies to help achieve that goal is a new breed of low-powered microprocessors that can vary the speeds at which they operate.
12. South Korean scientists clone first dog
13. South Korea's pioneering stem cell scientist has cloned a dog
14. Snuppy, the first cloned dog, appears with the three-year old male Afghan hound
whose cells were used to clone him.
15. Researchers have since cloned cats, goats, cows, mice, pigs, rabbits, horses, deer,
mules and gaur,
16. Researchers determined that the specimens are around 195,000 years old. 17. Many large cities are anything but beautiful.
18. If people want to solve the problem of waste, there is no time to be lost.
19. They must work out ways of making use of good things which are just thrown
away as waste.
20. When a car gets too old, it may not run any more. But the metal that the car was
made of is still good. It can be put to use again.
21. When a bottle is empty, it goes out in the trash. But bottle glass can be ground
into sand and used to pave streets.
22. Garbage from food can be changed into fertilizer. But first you have to fish out all the glass and metal.
23. Garbage can also be a good source for making building blocks, which are then
covered with concrete. 24. Now, more and more machines are designed for this purpose.
25. Some day, people will watch films in a magnificent cinema which has been built
out of garbage.
26. Future buildings, roads, and cities maybe made from garbage.
27. But so far, building beautiful cities out of garbage is only a dream.
28. A UFO is the reported sighting of an object or light seen in the sky or on land 29. UFOs (sometimes called flying saucers) became widely discussed only after the
first widely publicized U.S. sighting in 1947
30. At least 90 percent of UFO sightings can be identified as conventional objects,
although time-consuming investigations are often necessary for such identification.
31. Some persons nevertheless believe that UFOs are extraterrestrial spacecraft
32. UFO enthusiasts persist, however, and some persons even claim to have been
abducted and taken aboard UFOs
33. A very important world problem is the rapidly increasing pressure of population
on the land. 34. This enormous increase of population will create immense problems.
35. By AD. 2020, unless something terrible happens, there will be as many as
7000000000 people on the surface of the earth! So this is a problem which you are going to see in your lifetime.
36. However, such vehicles could be some 25 years from appearing on the market. 37. Efforts to build flying vehicles in the past have not been very successful. 38. Temperatures in some parts of the country have eased a bit over the weekend. 39. The air-conditioner has established itself well in the hearts of Americans
40. The first widespread use of air-conditioners came during the 1920 when movie theaters used what they called man-made weather to lure customers to the silver scream.
41. Many Americans are observing the fifth anniversary of one of the nation's worst
natural disasters
42. Death and destruction from the hurricane and its effects extended along the Gulf
Coast.
43. Severe ocean storms in the northern part of the world usually develop in late
summer or early autumn near the equator.
44. Ocean storms develop when the air temperature in one area is different from the
temperature nearby. 45. The strongest, fastest winds of a hurricane blow in the area known as the
eyewall. It surrounds the center, or eye, of the storm.
46. Weather scientists use computer programs to create models that show where a storm might go.
47. Doctors in hospital emergency rooms often see accidental poisonings.
48. If you know first aid methods, you can be calmer and more helpful in case of
emergency.
49. However, human activities are threatening the world's coral reefs.
50. The researchers say the United States represents more than fifty percent of the trade in coral and reef fish
51. Few creatures on earth are as good as sharks at finding their dinners.
52. People often say that a shark follows its nose to its meals. Now, scientists have
learned more about how those noses work to help the much-feared fish direct its movements.
53. Extremely hot weather is common in many parts of the world.
54. Although hot weather just makes most people feel hot, it can cause serious
medical problems, even death.
55. The most common health problem linked to hot weather is heat stress.
56. Weather scientists use computer programs to create models that show where a storm might go.
57. A new report says the Arctic is experiencing some of the most severe climate
change on Earth.
58. Chicken eggs are used in the process to make flu vaccine. 59. A study suggests that dirty air can reduce lung development.
60. The scientists found that children who lived in areas with the dirtiest air were five
times more likely to grow up with weak lungs.
61. The damage from dirty air was as bad as that found in children with parents who
smoke.
62. Americans are expected in January to get new advice from the government about
what to eat and what to avoid.
63. The researchers say diet drinks and unsweetened fruit juice did not appear to
cause an increased risk of diabetes.
64. Doctor Stampfer says it is easier to gain weight from calories in drinks than in
foods.
65. In real life, scientists have learned something new about this creature which first
appeared on Earth about seventy-five million years ago. Dinosaur
66. An arboretum is a place where trees and plants are grown for scientific and
educational purposes. 67. The goal of the Arboretum is to carry out studies and provide education in an
effort to improve the environment.
68. The World Health Organization says iron deficiency is the most common nutritional disorder in the world.
69. Health experts say iron deficiency is the most common preventable nutritional
problems.
70. Iron is stored in bone marrow and two organs -- the spleen and liver.
71. The World Health Organization estimates that each year almost five million
people worldwide die from the effects of smoking. 72. Smoking causes or increases the risk of many diseases. These include cancer and
heart disease.
73. A small, new study has found that sudden emotional stress can cause heart failure
in mostly healthy older women.
74. Scientists have discovered fourteen kinds of vitamins. They are known as
vitamins A, the B group, C, D, E and K.
75. Computer industry experts say wi-fi is the fastest growing part of the computer
industry. 1．传统意义上，北美国际汽车展已经成为汽车工业最新产品的奢华揭幕。 2． 一项新的提高农作物产量的国际行动可以提高南亚六百万农民的收入，帮助这个世界上最贫困的地区之一的人民抵抗饥饿。
3．美国宇航局正在庆祝阿波罗8号成功执行太空任务的第四十个周年纪念日。 4． 对于美国宇航局来说，2008年将因他们执行了太空任务，在火星上有新发现，在太阳系内及其之外发现了新的秘密而被载入史册。
5． 三条主要的从意大利到北美的互联网电缆因本年度第二次这样的事故受到无法想象的严重破坏，致使埃及和几个其他的阿拉伯国家陷入通讯危机。 6． 清洁能源指的是那些不污染空气、陆地和海洋的能源，包括：太阳能、风能、
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