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Some of the TestKing routers have been configured with default routes. What are some of the advantages of using default routes?（）
A . They establish routes that will never go down.
B . The keep routing tables small.
C . They require a great deal of CPU power.
D . The allow connectivity to remote networks that are not in the routing table.
E . They direct traffic from the Internet into corporate networks.
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What are some of the characteristics of the OSPF routing protocol?（）
A . It confines network instability to a single area of network.
B . It increases the routing overhead of the network
C . It supports VLSM
D . It routes between Autonomous Systems.
E . It allows extensive control of routing updates
F . None of the above
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What are some virtues of implementing end-to-end VLANs？（）
A . End-to-end VLANs are easy to manage.
B . Users are grouped into VLANs independent of a physical location.
C . Each VLAN has a common set of security and resource requirements for all members.
D . Resources are restricted to a single location.
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On（）side of the street there are some trees.
A . both
B . either
C . every
D . all
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What are some of the characteristics of a typical VLAN arrangement?（）
A . VLANs logically divide a switch into multiple, independent switches at Layer 2.
B . Trunk links can carry traffic for multiple VLANs.
C . VLAN implementation significantly increases traffic due to added trunking information.
D . A VLAN can span multiple switches.
E . VLANs typically increase the number of switches needed
F . VLANs typically decrease the number of switches needed
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Kort nozzles are installed around the propellers of some vessels to（）.
A . Increase the thrust of the propeller
B . Protect the propeller from striking sawyers
C . Prevent the propeller from striking barges towed on the ship
D . Prevent the propeller from touching bottom in low water
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Some of the larger birds can remain stationary in the air for several minutes
A . silent
B . motionless
C . seated
D . true
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What are some characteristics of the typical VLAN arrangement?（）
A . VLANs logically divide a switch into multiple, independent switches at Layer 2.
B . Trunk links can carry traffic for multiple VLANs.
C . VLAN implementation significantly increases traffic due to added trunking information.
D . A VLAN can span multiple switches.
E . VLANs extend the collision domain to include multiple switches.
F . VLANs typically decrease the number of multiple switches.
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What are some of the advantages of using a router to segment the network?（）
A . Filtering can occur based on Layer 3 information.
B . Broadcasts are eliminated.
C . Routers generally cost less than switches.
D . Broadcasts are not forwarded across the router.
E . Adding a router to the network decreases latency.
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Some TV programs are interesting but some others are（）and full of violence.
A . frightening
B . frightened
C . to be frightening
D . to be frightened
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1. What are some of Shakespeare's representative works?
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Pigs cannot fly, so they are not birds. Indicate which of the following is a single suppressed premise that is sufficient to make this argument valid.
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Some examples of popular sales promotions activities are ____.
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Some of experiments ___ are easy to perform.
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The author uses the example of Angry Birds to illustrate that many game apps on smartphones are both entertaining and educational.
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Why are some of the works of Steinbeck considered controversial?
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What are some of the well-known places of interest in Britain?
A、Hyde Park
B、Buckingham Palace
C、The Statue of Liberty
D、No. 10 Down Street
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Birds are literally half-asleep--with one brain hemisphere alert and the other sleeping, according to a new study of sleeping ducks.
Earlier Studies have documented half-brain sleep in a wide range of birds. The brain hemispheres take turns sinking into the sleep stage characterized by slow brain waves. The eye controlled by the sleeping hemisphere keeps shut, while the wakeful hemisphere's eye stays open and alert. Birds also can sleep with both hemispheres resting at once.
Decades of studies of bird flocks led researchers to predict extra alertness in the more vulnerable, end-of-the-row sleepers. Sure enough, the end birds tended to watch carefully on the side away from their companions. Ducks in the inner spots showed no preference for gaze direction.
Also, birds dozing (打盹) at the end of the line resorted to single-hemisphere sleep, rather than total relaxation, more often than inner ducks did. Rotating 16 birds through the positions in a four-duck row, the researchers found outer birds half-asleep during 32 percent of dozing time versus about 12 percent for birds in internal spots.
"We believe this is the first evidence for an animal behaviorally controlling sleep and wakefulness simultaneously in different regions of the brain," the researchers say.
The results provide the best evidence for a long-standing supposition that single- hemisphere sleep evolved as creatures scanned for enemies. The preference for opening an eye on the. lockout side could be widespread, he predicts. He's seen it in a pair of birds' dozing side-by-side in the zoo and in a single pet bird sleeping by a mirror. The mirror-side eye closed as if the reflection were a companion and the other eye stayed open.
Useful as half-sleeping might be, it's only been found in birds and such water mammals (哺乳动物) as dolphins, whales, and seals. Perhaps keeping one side of the brain awake allows a sleeping animal to surface occasionally to avoid drowning.
Studies of birds may offer unique insights into sleep. Jerome M. Siegel of the UCLA says he wonders if birds' half-brain sleep "is just the tip of the iceberg (冰山) ". He speculates that more examples may turn up when we take a closer look at other species.
A new study on birds' sleep has revealed that ______
A．half-brain sleep is found in all kinds of birds
B．half-brain sleep is characterized by accelerated brain waves
C．birds can control their half-brain sleep consciously
D．birds always sleep with the whole of their brain at rest
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I have many friends, some of them are businessmen .
A B C D
____________
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【C1】______ nearly a hundred years of powered flight, scientists are still trying to figure out how birds fly.
Researchers have learned that the slapping noise pigeons make when they suddenly take off is the sound of super charged lift. They call it the "clap fling" effect.
Here at SRI International scientists try to duplicate the pigeons' thrust. A flashing strobe reveals the secret.
Scott Stanford, a scientist at SRI, says, You re looking at the clap fling effect, where the two wings will come together and peel apart 【C2】______ each other, thus augmenting lift 【C3】______ drawing air from the top to the bottom. "
This mechanical bug won't get off the ground. 【C4】______ its flapping wings demonstrate a potential propulsion system for robotic birds: man-made rubbery muscle.
Roy Kornbluh works at SRI. "There, I'm turning the voltage on and off, and you can see when the voltage is on, the material is larger 【C5】______ when the voltage is off."
Super computers show high-speed airflows over supersonic aircraft.
But scientists have only begun to see how air flows 【C6】______ really low speeds.
Professor Max Platzer of the Naval Postgraduate School, says, "The flapping wing is generating a thrust, this way, this is the basic physics of the phenomenon."
It's pelicans--not pigeons--the Navy is looking at. The Navy is looking at the smooth easy flight of pelicans low over water--called "ground effect." Researchers at the Naval Postgraduate School are trying to imitate the pelican's efficiency.
Assistant Professor Kevin Jones of the Naval Postgraduate School says, " 【C7】______ flapping the wings, symmetrically, we're 【C8】______ effect imitating ground effect. We now have the same feature a bird sees when it's flying, over a ground plane."
An electric motor drives the flapping wings. Researchers here are working 【C9】______ ways to beam power to the tiny bird.
David Jenn of the Naval Postgraduate School says, "There's no battery inside of here, so we're going to set this inside the radar beam, and the energy is extracted from the radar beam and will be used to propel the motor."
Scientists are learning it's one thing to build an airplane, 【C10】______ quite another to build a bird.
【C1】______
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What are some of the characteristics of a typical VLAN arrangement？（）
A. VLANs logically divide a switch into multiple, independent switches at Layer 2.
B. Trunk links can carry traffic for multiple VLANs.
C. VLAN implementation significantly increases traffic due to added trunking information.
D. A VLAN can span multiple switches.
E. VLANs typically increase the number of switches needed
F. VLANs typically decrease the number of switches needed
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A pet is an animal that【21】in your house. Over half the families in North America own pets. The most popular【22】axe dogs, fish and birds. Rabbits, hamsters and turtles are also popular.【23】some unpopular animals such as frogs, mice and snakes are pets.
People first【24】to keep pets about 12,000 years ago. The first pet was a dog. The dog【25】not become a pet because people【26】it was cute. It【27】a pet because it was useful. People used the dog for many things. The dog warned people【28】danger so wild animals didn't attack people. It also ate leftover food. Later, dogs helped people take care【29】cows and sheep on farms.
Cats did not【30】pets for a long time. When the Egyptians first【31】to grow grain, mice ate it. The Egyptians were【32】to tame cats.
Today, people keep many【33】of pets. Animals such as canaries, parrots, mice and hamsters live in cages. They need people to bring them food and water and to keep their cages clean. Other animals, such as dogs and cats, need food and water, but they【34】take care of themselves【35】. They are good pets for people because they don't need much care.
(36)
A．lives
B．stays
C．sleeps
D．plays
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Scientists have established that influenza viruses taken from man can cause the disease in animals. In addition, man can catch the disease from animals. In fact, a great number of wild birds seem to carry the virus without showing an evidence of illness. Some scientists concluded that a large family of influenza viruses may have evolved in the bird kingdom, a group that has been on the earth 100 million years and is able to carry the virus without contracting the disease. There is even convincing evidence to show that virus strains are transmitted from place to place and from continent to continent by migrating birds.
It's known that two influenza viruses can recombine when both are present in an animal at the same time, the result of such recombination is a great variety of strains containing different H and N spikes. This raises the possibility that a human influenza virus can recombine with an influenza virus from a low animal to produce an entirely new spike. Research is underway to determine if that is the way that major new strains come into being, another possibility is that two animal influenza strains may recombine in a pig, for example, to produce a new strain which is transmitted to man.
According to the passage, scientists have discovered that influenza viruses ______.
A．cause ill health in wild birds
B．do not always cause symptoms in birds
C．are rarely present in wild birds
D．change when transferred from animals to man
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很多动物种类即将面临灭绝的危险Many species of animal are in danger of extinction.
