1 . Most animal species in the world have developed some sort of natural camouflage that helps them find food and avoid attack. The specific nature of this camouflage varies considerably from species to species.
Camouflage develops differently depending on the physiology and behavior of an animal.
An animal's environment is often the most important factor in what the camouflage looks like. The simplest camouflage technique is for an animal to match the "background" of its surroundings.
Since the ultimate goal of camouflage is to hide from other animals, the physiology and behavior of an animal's predators or prey is highly significant.
In addition to background-matching coloration, many animals have distinctive designs on their bodies that serve to conceal them. These designs, which might be spots, stripes or a group of patches, can help the animal in a couple of ways. First, they may match the pattern of "the model", the background of the animal's surroundings. Second, they may serve as visual disruptions. Usually, the patterns are positioned out-of-line with the body's contours (外形).
Other animals use a more aggressive sort of mimicry. Several moth species have developed striking designs on their wings that resemble the eyes of a larger animal. The back of the hawk moth caterpillar actually looks like a snake head, a frightening visage for most predators he moth would come across.
Mimicry is a different approach than ordinary camouflage, but it works toward the same end. By developing a certain appearance, an animal species makes itself a harder target for predators and a sneakier hunter for prey. As animal species evolve, they become more and more in tune with their environment.
| A．Often, these sorts of adaptations are more effective survival tools than an animal's more aggressive weapons of defense (teeth, claws, beaks). |
| B．This disruptive coloration is particularly effective when animals in a species are grouped together. |
| C．For example, an animal that swims in large schools underwater will develop different camouflage than one that swings alone through the tees. |
| D．An animal will not develop any camouflage that does not help it survive. |
| E．In this case, the various elements of the natural habitat may be referred to as the "model" for the camouflage. |
| F．That is, the pattern seems to be a separate design superimposed on top of the animal. |
2 . China's Chang'd has been operating flawlessly since it landed on the far side of the Moon in January 2019. Its arrival was later followed by the appearance of Beresheet, a probe built by the Israeli non-profit organization Spacell. It reached the Moon in April but crashed during its landing. Spacell has since announced that it intends to take another
After the
One reason for this
David Parker from the European Space Agency sees particular
Mastering a harsh environment that is distant will require us to overcome all sorts of technological hurdles. Then we will be better
There is, however, another more poignant (辛酸的) reason for returning to the Moon. Six Apollo missions made it to the lunar surface, each crewed by two men.
When the Apollo astronauts were flying to the Moon, it seemed like science fiction come true. It would be good if we could bring back that sense of
| A．luck | B．risk | C．look | D．shot |
| A．revealed | B．unlocked | C．exposed | D．demonstrated |
| A．increasing | B．initial | C．ultimate | D．genuine |
| A．died out | B．worn off | C．passed down | D．left behind |
| A．shift | B．evolution | C．passion | D．preference |
| A．favorable | B．available | C．comparable | D．accountable |
| A．association | B．harmony | C．agreement | D．parallels |
| A．imported | B．mirrored | C．transferred | D．applied |
| A．promise | B．contribute | C．resolve | D．intend |
| A．interference | B．destruction | C．involvement | D．emergence |
| A．informed | B．enlightened | C．armed | D．converted |
| A．Thus | B．Nevertheless | C．Otherwise | D．Furthermore |
| A．Despite | B．Beyond | C．Regarding | D．Given |
| A．tragedy | B．destiny | C．blow | D．revelation |
| A．fulfillment | B．wonder | C．duty | D．identity |
| A. normal B. continued C. trapped D. remove E. short F. urged G. commit H. anniversary I. end J. increases K. record |
2020 has been an extreme year for hurricanes , wildfires and heat waves around the world. New reports from United Nations agencies list this year's record-breaking weather and the burning of fossil fuels as causes of
U.N. Secretary-General Antonio Guterres recently
The secretary-general's comments come as the U.N. prepares for a Dec. 12 online climate meeting in France on the 5th
In a speech given at New York’s Columbia University , Guterres said, “The state of the planet is broken ,Humanity is waging war on nature. This is suicidal Destructive fires and floods, cyclones and hurricanes are increasingly the new
In a report ,the World Meteorological Organization (WMO) said this year is set to
Guterres saw hope that more than 100 countries have promised that by 2050 they will not be adding more heat-trapping gases to the atmosphere than trees and technology can
4 . Every dog owner knows that saying Good dog! A happy, high-pitched voice will bring about a flurry of joyful tail wagging in their pet.
That makes scientists curious. What exactly happens in your dog’s brain when it hears praise? And is it similar to the way our own brain processes such acoustic information?
When a person gets a compliment, the more primitive subcortical(皮下的)auditory regions first react to the intonation(声调) , the emotional force of spoken words. Next, the brain taps the more recently evolved auditory cortex(皮质)to figure out the meaning of the words, which is learned.
It’s an important question. Dogs are speechless species.
When the scientists studied scans of the brains of pet dogs, they found that theirs, like ours, processed the sounds of spoken words in a multi-step manner. They analyze first the emotional component with the older region of the brain, the subcortical regions. Subsequently, they deal with the words’ meaning with the newer part, the cortex.
Previous studies have shown that many animals, from songbirds to dolphins, use the subcortex to process emotional hints.
It’s likely that human language evolved from such hints. We employ the same neurological systems to develop speech.
| A．It is widely recognized that the dog has a complex structure of brain, similar, in a way, to that of human’s. |
| B．But they respond correctly to our words. |
| C．Animals are found to have adopted various mechanisms to defend against enemies. |
| D．They are capable of obtaining mood implications even though they can’t talk. |
| E．It has been discovered that dogs’ brains, like those of humans, compute the intonation and meaning separately. |
| F．Domesticated animals have evolved alongside humans for the past thousands of years. |
Imagine living on the edge of a vast desert, which is moving quietly closer to your village every day and covering your fields. The desert is on the move. This is called desertification.
Desertification occurs in regions close to an already existing desert. It generally arises from two related causes. The first is over-use of water in the area. There is not enough water in any case, and if it is not carefully used, disaster can follow. As time goes on, water shortages make farming more and more difficult. In some places, locals can remember local lakes and marshes which were once the homes for all kinds of fish and birds. They have been completely buried by the sand now. Farmers leave the land, and fields are replaced by deserts.
The second cause is misuse or over-use of the land. This means that the wrong crops are planted and need more water than is available. Ploughing large fields and removing bushes and trees means that the wind will blow away the soil. Once the soil is lost, it is hard to replace, and if there is rain, it has nowhere to go, and brings no benefit.
It is not only the farmers and villagers who suffer. Every spring, the skies over some of eastern cities, thousands of kilometers away from the deserts, can be darkened by sandstorms. Dust from deserts can have a great effect on weather systems. While desertification is perhaps being partly caused by global warming, these sandstorms can make global warming worse by adding to what is known as the greenhouse effect.
What can be done to slow down or stop the process of desertification? A great deal of work is already under way. Obviously first steps are to find new water sources. Tree planting can help, by providing barriers between desert and rich field. Some types of grass also hold the soil together, and stop the wind taking it. Without these efforts, it will be harder and harder to stop the world’s deserts in their tracks, and more and more farmers will give up and head for cities. The lesson to be learnt lies beneath the sand.
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6 . In recent weeks, a group of 15 wild elephants on a long, strange trip out of the jungles of far southwestern China have attracted millions of people across the country. Since the elephants left a wildlife reserve near China’s border with Laos and Myanmar last year, they have
Millions have
Videos of the
Some specialists at the Chinese Academy of Sciences have assumed that a recent solar storm may have
In recent days, the
| A．hunted | B．located | C．marched | D．invaded |
| A．taken over | B．tuned in | C．got together | D．showed up |
| A．fascinated | B．concerned | C．bored | D．frightened |
| A．declines | B．booms | C．reverses | D．settles |
| A．trembling | B．imposing | C．striking | D．parading |
| A．global | B．wrong | C．viral | D．crazy |
| A．In response | B．In addition | C．In turn | D．In theory |
| A．capture | B．tend | C．surround | D．track |
| A．trap | B．raise | C．steer | D．tame |
| A．content | B．contrast | C．context | D．consequence |
| A．abused | B．detected | C．awakened | D．liberated |
| A．urge | B．possibility | C．memory | D．permission |
| A．material | B．value | C．habitat | D．size |
| A．consistent | B．initial | C．restricted | D．separated |
| A．concern | B．control | C．quarrel | D．reflection |
7 . Ecotourism is often regarded as a form of nature-based tourism and has become an important alternative source of tourists. It is broadly defined as low
Ecotourism and other forms of sustainable travel have their
Since then, several different organizations specializing in ecotourism have developed and many different people have become experts on it. Martha D. Honey, PhD, a co-founder of the Center for Responsible Tourism,
Opportunities for ecotourism exist in many different locations worldwide and its activities can vary
Madagascar, for instance, is famous for its ecotourist activity as it is a biodiversity hotspot, but also has a high priority for environmental conservation and is devoted to reducing poverty. Conservation International says that 80% of the country's animals and 90% of its plants are
Because the island's government is
Despite the popularity of ecotourism in the above-mentioned examples, there are several
Critics of ecotourism also cite that increased tourism to
Ecotourism is also said by critics to have a negative impact on
Regardless of these criticisms though, ecotourism and tourism, in general, are increasing in popularity all over the globe and tourism plays a large role in many worldwide economies.
1.| A．impact | B．frequency | C．standard | D．profit |
| A．undergoes | B．supervises | C．benefits | D．ignores |
| A．agencies | B．impacts | C．obstacles | D．origins |
| A．addicted | B．opposed | C．reduced | D．attached |
| A．in particular | B．in a sense | C．as a result | D．for example |
| A．widely | B．accordingly | C．respectively | D．naturally |
| A．subject | B．fatal | C．peculiar | D．close |
| A．residents | B．species | C．properties | D．locations |
| A．restricted | B．accustomed | C．connected | D．committed |
| A．After all | B．On occasion | C．By contrast | D．In addition |
| A．perspectives | B．consequences | C．criticisms | D．methods |
| A．briefly | B．truly | C．luckily | D．carefully |
| A．sensitive | B．inaccessible | C．cultivated | D．vast |
| A．agricultural | B．remote | C．local | D．divided |
| A．depend on | B．differ from | C．deal with | D．dig into |
The UK government recently has made a plan to reduce waste that shifts the responsibility for disposal (处置) from the state to the companies that make it.
The legislation (法律条文) requires waste producers to pay into the system
The demand for legislation like the tough attitude the UK
What is absolutely certain is that local governments will save a lot of money as the responsibility shifts to the polluters. That could be
In many countries, kitchen and gardening waste makes up of the biggest part of waste. This type of waste,
9 . Hibernation is a complex solution to a simple problem. In winter, food is scarce. To survive this seasonal starvation, animals, such as the arctic ground squirrel and black bear, hibernate so that physiological shifts keep them alive despite the lack of food, water and movement. Researchers and doctors alike are interested in how these hibernation tricks could help humans with their own health.
THREAT: Stroke
INSIGHT: Blood flow in the brain of a hibernating arctic ground squirrel drops to a tenth of normal. Typically such oxygen shortage would cause a stroke. But these squirrels can survive all winter because their metabolism lowers to 2 percent of its summer rate—requiring much less oxygen to maintain. If doctors could similarly lower the metabolism of a human patient immediately after a stroke—perhaps by cooling the body—they might prevent permanent brain damage, says Brian Barnes, a biologist at the University of Alaska Fairbanks.
THREAT: Diabetes
INSIGHT: People who gain a lot of weight often stop responding to insulin, which regulates the amount of glucose that cells take up from the blood. Yet grizzly bears gain 100 pounds or more each autumn and somehow avoid diabetes. A recent study found that the grizzlies' fat cells become more sensitive to insulin as they prepare for the winter, allowing the bears to keep processing and storing sugar. Scientists at biotechnology company Amgen are now testing whether making slight changes to the same protein that controls sensitivity in diabetic humans could have similar results.
THREAT: Osteoporosis
INSIGHT: If a human were to lie still for long periods without food, his or her bones would slowly degrade. A black bear, however, emerges from its cave after winter just as strong as ever because its bone is recycled at 25 percent of normal levels during hibernation. Researchers at Colorado State University are now trying to identify the hormones that control this extreme limit on bone turnover. They aim to create a drug for people at risk for osteoporosis that similarly protects bone density.
THREAT: Heart Disease
INSIGHT: During heart surgery, a patient becomes short of oxygen when the heart stops beating. To cope, the body switches from aerobic to anaerobic metabolism. Unfortunately, the change creates lactic acid, which can kill cells if it builds up. Damage of this kind does not occur in hibernating arctic ground squirrels, likely because they break down more fats than sugars even after the heart has slowed to just one beat per minute. Researchers at Duke University and the University of Alaska Fairbanks are now working to identify how this species prioritizes fat as fuel in low-oxygen conditions. Finding a way to get heart surgery patients to do the same may reduce injury to organs during procedures.
1. What is the passage mainly about?| A．What humans can learn from animals that sleep for months on end. |
| B．What health threats humans are facing while they are under treatment. |
| C．How humans can survive from the same tough conditions as animals do. |
| D．How health threats can be avoided if humans are with certain animals. |
| A．stroke | B．diabetes | C．osteoporosis | D．heart disease |
| A．Metabolism usually consumes a small amount of oxygen. |
| B．Fat cells are less sensitive to insulin than other cells. |
| C．Lying still for a long time will affect bone density. |
| D．Doctors are seeking ways to keep patients' hearts beating in surgery. |
10 . Throughout history, many lives have been lost at the hands of severe weather. Meteorologists (气象学家) and scientists alike are always investigating new ways to increase the warning time for storms, with the hope of reducing the
Meteorologists and scientists have been able to successfully track severe thunderstorms and possible tornadoes by using an advanced tracking system called NEXRAD (Next-Generation Radar). NEXRAD is a tracking network
These
If the storm is severe enough, then the National Weather Service (NWS) will
On the television screen you will see several colors on the precipitation map,
When local weather radar in Atlanta, Georgia reported high winds,
Thanks to this technology, most residents received the severe weather reports early enough to seek
| A．loss | B．increase | C．protection | D．value |
| A．changing | B．controlling | C．predicting | D．guiding |
| A．faced with | B．exposed to | C．involved in | D．made up of |
| A．structure | B．system | C．mode | D．style |
| A．figures | B．data | C．readings | D．statistics |
| A．Most likely | B．Most evidently | C．Most interestingly | D．Most importantly |
| A．decide | B．estimate | C．handle | D．issue |
| A．By the way | B．In that case | C．To some extent | D．On the contrary |
| A．vital | B．reasonable | C．normal | D．available |
| A．expanding | B．spreading | C．ranging | D．extending |
| A．proper | B．specific | C．typical | D．regular |
| A．straight | B．unique | C．general | D．circular |
| A．process | B．threat | C．warning | D．sign |
| A．indicating | B．recognizing | C．revealing | D．recommending |
| A．rescue | B．residence | C．support | D．shelter |
