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Radar is an example of acronym.（)
Radar is an example of acronym.()
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Radar is an example of acronym.()
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更多“Radar is an example of acronym.（)”相关的问题
第1题
Space-Age Archeology
It's a strange partnership, but a very effective one: Satellites and space-shuttle-carried radar are helping archeologists. How？ By "seeing" through sand or through treetops to locate important archeological sites.
The traditional tools of archeologists are shovels and picks. But high technology is making the archeologist's work and time far more productive.
Take, for example, the second 1981 flight of the Space Shuttle Challenger. During that mission, a powerful, experimental radar was pointed at a lifeless stretch of desert in Egypt called the Selima Sand Sheet (part of the Sahara Desert). To everyone's surprise, the radar penetrated through the sand to the harder rock beneath. On the surface, there is a little indication that Africa's Sahara Desert was never anything but a desert. When the archeologists studied the radar images, they saw what seemed to be impossible: there was sand-buried landscape. that was shaped by flowing water; traces of ancient riverbeds appeared to be over nine miles wide, far wider than most sections of the present-day Nile River. Today, the area is one of the hottest, driest desert in the world.
Archeologists dug pits along the old river banks and found clues to the past: stream-rounded pebbles (鹅卵石), Stone-Age axes, broken ostrich (鸵鸟) eggshells, and the shells of land snails. The archeologists were quite pleased with these findings. For years, they'd been finding stone axes scattered through, the-desert, and couldn't understand why. Now we know that early humans were living on the banks of old rivers, and left their beautiful tools behind. Some are so sharp that you could shave with them.
More recently, Landsat 4, a special Earth-mapping satellite, aided in the discovery of ancient Mayan ruins in Mexico. Landsat can, with the help of false-color imagery, "see through" much of the area. Armed with these maps, a five-person expedition took to the air in a helicopter.
By the end of the second day, the team found a stretch of walled fields that expedition members said look like "old New England fences". They just go on, non-stop, for 40 miles. Later in the week, an ancient village was pinpointed, as was the "lost" city of Oxpemul, once found in the early 1930's but quickly reclaimed by the jungle. The findings made them able to map the extent of the Mayan civilization in about five days. Working on foot, it would, have taken at least 100 years.
With the help of the space-shuttle-carried radar, archeologists found
A．a new stretch of the Sahara desert.
B．traces of ancient riverbeds under the Sahara Desert.
C．some traditional archeological tools in the Sahara Desert.
D．a mountain beneath the Sahara Desert.
第2题
Until recently, the observation--intensive approach needed for accurate, very short-range forecasts, or "Nowcasts", was not feasible. The cost of equipping and operating many thousands of conventional weather stations was prohibitively high, and the difficulties involved in rapidly collecting and processing the raw weather data from such a network were insurmountable. Fortunately, scientific and technological advances have overcome most of these problems. Radar systems, automated weather instruments, and satellites are all capable of making detailed, nearly continuous observation over large regions at a relatively low cost. Communications satellites can transmit data around the world cheaply and instantaneously, and modern computers can quickly compile and analyzing this large volume of weather information. Meteorologists and computer scientists now work together to design computer programs and video equipment capable of transforming raw weather data into words, symbols, and vivid graphic displays that forecasters can interpret easily and quickly. As meteorologists have begun using these new technologies in weather forecasting offices, Nowcasting is becoming a reality.
What does the passage mainly discuss？
A．Computers and weather.
B．Dangerous storms.
C．Weather forecasting.
D．Satellites.
第3题
Implied but not stated ______ .
A．Laser-dopple radar is more accurate than microwave radar
B．Microwave radar may not ensure absolute precision in measuring varying speeds
C．The light-beam radar can measure only slow speeds with accuracy
D．Microwave radar operates at a higher frequency than laser-dopple radar
第4题
Laser-dopple radar is especially valuable in space missions because it ______ .
A．is one thousand times more precise than microwave radar
B．provides precise measures of the velocity of space vehicles
C．is a new system of radar
D．can measure the movement of a spaceship less accurately than a microwave radar
第5题
Laser-dopple radar is especially valuable in space missions because it ______.
A．is one thousand times more precise than microwave radar
B．provides precise measures of the velocity of space vehicles
C．is a new system of radar
D．can measure the movement of a spaceship less accurately than a microwave radar
第6题
Which of the following statements is implied but not stated？
A．Microwave radar operates at a higher frequency than laser-doppler radar.
B．Laser-doppler radar is more accurate than microwave radar.
C．The light-beam radar can measure only slow speeds with absolute accuracy.
D．Microwave radar does not insure absolute precision in measuring varying speeds.
第8题
Radar enabled the English ______.
A．detect German planes on their way to London
B．direct the outnumbered RAF planes effectively
C．confuse German bomber pilots
D．both A and B
第9题
Ask them to______ carefully the planes radio and radar system.
A．check on
B．check off
C．check out
D．check up
第10题
Implied but not stated ______.
A．Laser-dopple radar is more accurate than microwave radar
B．Microwave radar may not ensure absolute precision in measuring varying speeds
C．The light-beam radar can measure only slow speeds with accuracy
D．Microwave radar operates at a higher frequency than laser-dopple radar
