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Pollutants in the air aren’t always visible and come from many different sources. Smog hanging over cities is the most familiar and obvious form of air pollution. But there are different kinds of pollution - some visible, some invisible - that contribute to global warming. Generally any substance that people introduce into the atmosphere that has damaging effects on living things and the environment is considered air pollution. Carbon dioxide, a greenhouse gas, is the main pollutant that is warming Earth. Though living things emit carbon dioxide when they breathe, carbon dioxide is widely considered to be a pollutant when associated with cars, planes, power plants, and other human activities that involve the burning of fossil fuels such as gasoline and natural gas. In the past 150 years, such activities have pumped enough carbon dioxide into the atmosphere to raise its levels higher than they have been for hundreds of thousands of years. Other greenhouse gases include methane - which comes from such sources as swamps and gas emitted by livestock - and chlorofluorocarbons (CFCs), which were used in refrigerants and aerosol propellants until they were banned because of their deteriorating effect on Earth’s ozone layer. Another pollutant associated with climate change is sulfur dioxide, a component of smog. Sulfur dioxide and closely related chemicals are known primarily as a cause of acid rain. But they also reflect light when released in the atmosphere, which keeps sunlight out and causes Earth to cool. Volcanic eruptions can spew massive amounts of sulfur dioxide into the atmosphere, sometimes causing cooling that lasts for years. In fact, volcanoes used to be the main source of atmospheric sulfur dioxide; today people are. Industrialized countries have worked to reduce levels of sulfur dioxide, smog, and smoke in order to improve people’s health. But a result, not predicted until recently, is that the lower sulfur dioxide levels may actually make global warming worse. Just as sulfur dioxide from volcanoes can cool the planet by blocking sunlight, cutting the amount of the compound in the atmosphere lets more sunlight through, warming the Earth. This effect is exaggerated when elevated levels of other greenhouse gases in the atmosphere trap the additional heat.
4. What is NOT mentioned as a feature of sulfur dioxide?

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There is always conflict between parents and children. However, they still should talk and share things with each other.

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In 1860 the United States was predominantly rural. Most people were engaged in  agriculture, and about 80 percent of the population actually resided on farms or in small villages. Only 20 percent lived in towns and cities of 2,500 or more, the census definition of an urban area after 1880. New York alone in 1860 had more than 1 million people, and only 8 cities could boast about a population of more than 100,000. Thereafter the transition from a rural to a predominantly urban nation was especially remarkable because of its speed. By 1900, urbanization, with all of its benefits, problems, and prospects for a fuller life, became the mark of modern America The changing physical landscape reflected the shift to an urbanized society. Railroad terminals, factories, skyscrapers, apartment houses, streetcars, electric engines, department stores, and the increased pace of life were all signs of an emerging urban America. Indeed, the vitality, dynamic quality, variety, and restless experimentalism in society centered in the urban communities where the only constant factor was change itself.  Urbanization did not proceed uniformly throughout the nation. New England and the Middle Atlantic states contained the highest percentage of city dwellers. In the Middle West, the growth of cities such as Chicago, Milwaukee, Cleveland, and St. Louis showed the importance of urbanization in that region. The three West Coast states also experienced rapid urban growth. In the South, urbanization developed much more slowly, although by 1910 the expansion of transportation, commerce, and industry had greatly increased the population of older cities such as New Orleans and stimulated the growth of new urban centers such as Birmingham. However, the South remained predominantly rural. Only somewhat more than 20 percent of the population in that region was urban by 1910.  In some regions the urban impact had a depressing effect upon the surrounding rural communities. Much of New England in the late nineteenth century presented a discouraging picture of abandoned farms and sickly villages as people forsook the countryside and rushed to the larger towns and cities. In the Middle West, particularly Ohio and Illinois, hundreds of townships lost population in the 1880’s.
1. What does the passage mainly discuss?

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Students are advised to tune out distractions and focus on study.

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It was practically the anthem for 2019 World Series, with tens of thousands of Washington Nationals fans clapping in unison and belting out “Baby Shark, doo-doo doo-doo doo-doo.” In Lebanon, it became a rallying cry after a video of protesters singing to soothe a frightened toddler went viral. And in many other places, the earworm has drawn ridicule, with late-night comedian Jimmy Kimmel suggesting its creator should be jailed for life. To the contrary, the catchy tune about a family of sharks has become so lucrative that the Korean family behind it is now sitting on a rapidly growing multimillion-dollar fortune. Kim Min-seok co-founded closely held SmartStudy Co. in 2010, and five years later its children’s educational brand, Pinkfong, released “Baby Shark”. His father runs Samsung Publishing Co., which also owns part of the startup. The family fortune, based on stakes held by Kim’s immediate relatives in those two companies, is now about $125 million – much of it thanks to the song. However, when asked, SmartStudy declined to comment on the family’s wealth. Shares of Samsung Publishing soared 89% the week the World Series began as local media reported on the song’s surging popularity among U.S. baseball fans. National outfielder Gerardo Parra began using it as his walk-up music, leading to crowd sing-alongs with shark-jaw gestures, scenes that echoed across TVs as the team broke out of an early season slump. They rode the wave all the way to the championship. Kim, 38, hardly set out to write a hit global song. After working at gaming companies including Nexon and developing content for kids at Samsung Publishing, he co-founded SmartStudy to focus on the growing market for educational content for smartphones.
3. Which of the following is NOT correct about Pinkfong?

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__ with an average of 320 days of sunshine a year, the coastline offers the perfect holiday destination for anyone ____ to switch off and unwind.

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By the end of the third millennium, people will all have access to basic utilities like  electricity and the internet. As a type of civilization, the overall energy consumption of everyone in the 30th century will be at a level of around 4×10²⁶ watts. In other words, the  energy utilization in a world full of working class consumers will be comparable to the luminosity of our parent star. So, the people of the future will inevitably need to fully harness the output of the Sun through the use of a vast array of satellite mega-structures that encircle the celestial body and capture the radiation it emits.  In requiring everyone to work together, the inclusive attitude of the future will cause everyone to grow much closer to one another, improving interpersonal relationships in neighborhoods the world over. By the year 3000, the whole of humanity will become a sort of poly-amorous society of mono-ethnic global citizens, living in a complex egalitarian intercontinental cooperative. Everyone will be part of multicultural communities within communities. Companies and credit unions will even be owned by their employees. People will all be very conscientious. Everyone will support the global economy, as well as ecology, of the world.  Humans will inhabit artificial urban jungles filled with buildings and sidewalks, while the other animals will inhabit natural rural jungles filled with wilderness and trails. Friends will walk through the crowded streets of the mega-cities of the future holding hands with one another. Public displays of affection will be customary among everyone. Casual bisexual encounters will be the norm. Everyone will care about everyone else. People will all accept each other, and help each other out, more and more as time goes on. The point is that eventually, everyone will finally get along. Humanity will progress to a point of collective compatibility as everyone sufficiently integrates and assimilates. From now until the year 3000, the several thousand languages currently spoken will reduce down to only about a hundred. More importantly, the nation-state members of the UN will all use the same form of electronic currency. As the countries of the world unify more and more, the metric system will become the universal standard of measurement. Things will become increasingly more common among everyone. This will bring everyone closer and closer together, each step of the way. In the end, cultural memes will all eventually just blend together in the great melting pot that is the world.  People will also change physically, along with mentally, too though. For instance, there will be an increase in both height and longevity, among people in general. In the year 3000 people will be about six feet tall, and live to be 120 years old, on average. They will experience a slight reduction in the size of their mouths, too. Improvements in nutritional science will revolutionize the world of medicine and alter the course of human evolution. Everyone will be genetically screened as an embryo to weed out defects and correct mistakes in their personal genome. 8th scale transhuman cyborgs will even go so far as to have 7 th  scale robotic integrations, with microscopic machines making them better. This will be terribly important because there will be very little diversity in the gene pool of the superhumans of the future, who are all bred to be what is considered ideal.
5. According to paragraph 3, which of the following is NOT true?

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On an Old Quarter thoroughfare of Hanoi, known as train street, locomotives rumble down an active track just inches away from homes and other buildings. The juxtaposition of train tracks and residential housing has made it hugely popular among travelers to the capital of Vietnam. But the municipal government of Hanoi has ordered that cafes alongside the heavily Instagrammed train tracks – which sprung up to cater to the tourism boom – must close. Authorities cite danger to human life as the primary motivator for the shutdown. The boiling point apparently came on Sunday, when a train traveling through Hanoi was forced to reroute because there were too many tourists on the tracks, which were built in 1902 by the French. “Though the railway cafes attract tourists, they are, in fact, violating some regulations,” Ha Van Sieu, vice chairman of the Vietnam National Administration of Tourism, told reporters at a press briefing. In 2018, Vietnam-based writer Dave Fox told CNN Travel that “overtourism is a new buzzword for something that has been going on a long time.” A longtime Hanoi resident, he watched as “train street” transformed from a cool novelty into a safety concern. “Travelers need to be mindful of optics,” he added. When it comes to overtourism, some destinations face more of a challenge than others. In Indonesia, moves have been made to greatly restrict traveler access to Komodo Island, home to the famous Komodo dragon. Initially, the country had considered shutting the island to tourists completely, but settled on a plan with limited access to visitors who could pay a high access fee. And nearby in Thailand, the heavily popular Maya Bay, made famous by the film “The Beach” has been closed since 2018 to repair the most severe outcome – environmental damage. 
3. The underlined word “buzzword” in the passage is closet in meaning to __________

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An important point to remember if you like spending time out in the open air is that the human head doesn’t work very well outdoors if it becomes too hot, cold or wet. That’s why a hat is a good investment, whenever you are planning to go out and about. Surprisingly, a single waterproof hat with a brim will do the (34)______ adequately in most conditions. In cold climates, the problem is that the head is (35)______ heat all the time. As much as fifty to sixty per cent of your body’s heat is lost through the head and neck, (36)______ on which scientist you believe. Clearly this heat loss needs to be prevented, but it’s important to remember that hats don’t actually keep you warm, they simply stop heat escaping. Just as important is the need to protect your neck from the effects of bright sunlight, and the brim of your hat will do this. If you prefer a baseball cap, (37)______ buying one that has a drop down ‘tail’ at the back to stop your neck getting sunburnt. And in wet weather (38)______, hats are often more practical than pooling up the hood of your waterproof coat because when you turn your head, the hat goes with you, whereas the hood usually does not.

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Simmons Research conducted a survey of American adults in order to learn how much Americans at large trust the media, and we are pleased to present the results in this first Simmons News Media Trust Index. We asked respondents to let us know how trustworthy or untrustworthy they found 38 of the largest and most well-known news sources commonly available in the US. News sources included represented a wide variety of mediums, including print, online, radio, and television with many of them operating across platforms. The average percentage of respondents who rated news sources as trustworthy or very trustworthy was just 40.1% - not a ringing endorsement for journalism in general. Topping the list across all news sources, and the only newspaper in the top five, was the Wall Street Journal with 57.7% of Americans trusting them. The major television network news organizations also fared quite well in our survey, taking the second (ABC 55.9%), third (CBS 55.4%), and sixth (NBC 54.1%) most trusted positions. Among cable news, the most trusted network in the US was ironically not American. BBC News was trusted by 55.2% of Americans and was the fourth most trusted news source. CNN, which touts itself as the “most trusted name in news,” trailed the list at number 14 with the trust of 46.1% of Americans. Forbes was the most trusted magazine and rounded out the top five, trusted by 54.2% of Americans. The New York Times and the Washington Post were both among the most trusted news organizations in our survey. The New York Times came in at the seventh position trusted by 53.8% of Americans, and the Washington Post in eighth trusted by 53.6%. USA Today (51.1%) and the Washington Times (50.0%) were the final two sources trusted by at least a majority of Americans. The least trusted news sources were all Internet-first and hyper-partisan in nature representing brands that have been consistently rated as misleading and inaccurate by factcheckers. The six organizations trusted least were split evenly between far-left and far-right news sources, and on average were trusted by only about one in four Americans. Daily Caller was the bottom of our list, with just 22.5% trusting them. They were followed by another extremely conservative platform, InfoWars, at 24.3% which was recently banned or had content deleted from Facebook, YouTube, iTunes, and Spotify for violating terms of service around hate speech, harassment, and bullying
2. The word “they” in paragraph 1 refers to _____.

What is 'extreme' weather? Why are people talking about it these days? 'Extreme' weather is an unusual weather event such as rainfall, a drought or a heat wave in the wrong place or at the wrong time. In theory, they are very rare. But these days, our TV screens are constantly showing such  extreme weather events. Take just three news stories from 2010: 28 centimetres of rain fell on Riode Janeiro in 24 hours, Nashville, USA, had 33 centimetres of rain in two days and there was record  rainfall in Pakistan.

The effects of this kind of rainfall are dramatic and lethal. In Rio de Janeiro, landslides followed,  burying hundreds of people. In Pakistan, the floods affected 20 million people. Meanwhile, other parts of the world suffer devastating droughts. Australia, Russia and East Africa have been hit in the last ten years. And then there are unexpected heat waves, such as in 2003 in Europe. That summer, 35,000 deaths were said to be heat-related.

So, what is happening to our weather? Are these extreme events part of a natural cycle? Or are they caused by human activity and its effects on the Earth's climate? Peter Miller says it's probably a mixture of both of these things. On the one hand, the most important influences on weather events are natural cycles in the climate. Two of the most famous weather cycles, El Niño and La Niña, originate in the Pacific Ocean. The heat from the warm ocean rises high into the atmosphere and affects weather all around the world. On the other hand, the temperature of the Earth's oceans is slowly but steadily going up. And this is a result of human activity. We are producing greenhouse gases that trap heat in the Earth's atmosphere. This heat warms up the atmosphere, land and oceans. Warmer oceans produce more water vapour - think of heating a pan of water in your kitchen. Turn up the heat, it produces steam more quickly. Satellite data tells US that the water vapour in the atmosphere has gone up by four percent in 25 years. This warm, wet air turns into the rain, storms, hurricanes and typhoons that we are increasingly experiencing. Climate scientist, Michael Oppenheimer, says that we need to face the reality of climate change. And we also need to act now to save lives and money in the future

Extreme weather can be caused by________.

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Can a performance go viral? Ben Platt’s should. As the title character in Dear Evan Hansen, the new musical from Benj Pasek and Justin Paul, he offers acting so precise yet so painfully lucid that it should overwhelm the operating systems by which most contemporary musicals operate. Platt’s gestures, his expressions, his phrasing, even his vocal range – which is impressive but tends to thin out toward the top notes – all combine to communicate the fretfulness, uncertainty and timorous goodness that define his character. He plays Evan, a friendless high school senior terrified of life, the universe, everything. His harried single mother, Heidi, (Rachel Bay Jones) tells him, “You can’t succeed if you never try.” Evan nods, but you can that he believes more strongly in the corollary: “If you don’t try, you can’t fail.” A therapist has instructed him to write pep-talk letters to himself. On the first day of school, one of them falls into the hands of Connor Murphy (Mike Faist), another outcast with drug problems and a look a peer describes as “school shooter chic”. When Connor kills himself, his parents find the letter and mistakenly believe that Evan was a friend to their son. At first this attention panics Evan, but he soon accepts the role and even briefly becomes an internet sensation. Often he is tempted to tell Connor’s family the truth, but he fears disappointing them and sacrificing his newfound confidence Watching Dear Evan Hansen, one often thinks of Next to Normal, another Second Stage show about a mentally distressed protagonist. But with its tuneful pop score and teenage protagonist, Dear Evan Hansen is a gentler affair, even as it takes occasional pains not to oversentimentalize the material. When Evan presents a surprisingly rosy picture of her brother, his sister Zoe (Laura Dreyfuss) sings, “Don’t say it wasn’t true/ That you were not the monster/ That I knew.” Near the play’s end, Platt positively glistens with sweat and spit and tears. Yet one never has the sense of an actor deliberately winding himself up to deliver a visceral performance. There’s obvious care taken in the way he offers Evan’s cringing smile, his swallowed laugh, his habit of pulling at his clothes as though searching for someone to hold onto. But all of these details feel lived, organic, unrehearsed. And Platt’s ability to convey emotion through song is simply superb and often deeply heartrending.  
5. The word “rosy” in paragraph 3 is closest in meaning to _______

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Improving girls’ educational levels has been demonstrated to have clear impacts on the health and economic future of young women, which in turn improves the prospects of their entire community. The infant mortality rate of babies whose mothers have received primary education is half that of children whose mothers are illiterate. In the poorest countries of the world, 50% of girls do not attend secondary school. Yet, research shows that every extra year of school for girls increases their lifetime income by 15%. Improving female education, and thus the earning potential of women, improves the standard of living for their own children, as women invest more of their income in their families than men do. Yet, many barriers to education for girls remain. In some African countries, such as Burkina Faso, girls are unlikely to attend school for such basic reasons as a lack of private latrine facilities for girls. Higher attendance rates of high schools and university education among women, particularly in developing countries, have helped them make inroads to professional careers with better-paying salaries and wages. Education increases a woman’s (and her partner and the family’s) level of health and health awareness. Furthering women’s levels of education and advanced training also tends to lead to later ages of initiation of sexual activity and first intercourse, later age at first marriage, and later age at first childbirth, as well as an increased likelihood to remain single, have no children, or have no formal marriage and alternatively, have increasing levels of long-term partnerships. It can lead to higher rates of barrier and chemical contraceptive use (and a lower level of sexually transmitted infections among women and their partners and children), and can increase the level of resources available to women who divorce or are in a situation of domestic violence. It has been shown, in addition, to increase women’s communication with their partners and their employers, and to improve rates of civic participation such as voting or the holding of office.
8. What can be the best title of the reading passage?

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It can be quite busy here during the tourist __________.

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This/ department store/ to the left/ post office.

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There is still no consensus about how the Neanderthals were driven to extinction,  leaving our Homo sapien ancestors without any competition. The disappearance of the native European Neanderthals is odd partly because their shorter, stockier bodies must have made them better able to withstand the colder temperatures that prevailed when their cousins from Africa entered Europe. With a smaller surface area the Neanderthal body would have been able to retain more heat. The once common assumption that the key was the inferior vocal abilities of the Neanderthal has since been disproved by research on the Neanderthal hyoid bone, located in the throat. The larger skull capacity and brain is another respect in which they do not seem to have been inferior.  It was once thought that proof of a superior intellect was to be found in the narrower Homo sapien stone tools known as “blades”, which were assumed to be more efficient than the broader “flakes” used by the Neanderthals. In a number of important respects, including durability, this idea has proved to be unfounded. However, the blades would have been more effective as tips for throwing spears whereas the stone flakes would have been limited to the kind of thrusting spears the Neanderthals are believed to have used. This could have combined with the greater agility of the Homo sapiens to give them a distinct advantage in hunting on open terrain. Crucial in this respect were the larger canals in the Homo sapien inner ear, providing a more acute sense of balance, in addition to the longer limbs and lighter build. The Neanderthal technique of hiding and lying in wait for passing animals ceased to be viable when the dense forests of Europe began to recede. After a period of co-existence with their cousins, the Neanderthals were slowly eradicated.
According to the passage, what is now believed about the stone tools used by the
1. Neanderthals compared to those of the Homo sapiens?

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Herman Melville, an American author best known today for his novel Moby Dick, was actually more popular during his lifetime for some of his other works. He traveled extensively and used the knowledge gained during his travels as the basis for his early novels. In 1837, at the age of eighteen, Melville signed as a cabin boy on a merchant ship that was to sail from his Massachusetts home to Liverpool, England. His experiences on this trip served as a basis for the novel Redburn (1849). In 1841, Melville set out on a whaling ship headed for the South Seas. After jumping ship in Tahiti, he wandered around the islands of Tahiti and Moorea.This South Sea island sojourn was a backdrop to the novel Omoo (1847). After three years awayfrom home, Melville joined up with a U.S. naval frigate that was returning to the eastern United States around Cape Horn. The novel White Jacket (1850) describes this lengthy voyage as a navy seaman. With the publication of these early adventure novels, Melville developed a strong and loyal following among readers eager for his tales of exotic places and situations. However, in 1851, with the publication of Moby Dick, Melville's popularity started to diminish. Moby Dick, on one level the saga of the hunt for the great white whale, was also a heavily symbolic allegory of the heroic struggle of humanity against the universe. The public was not ready for Melville's literary metamorphosis from romantic adventure to philosophical symbolism. It is ironic that the novel that served to diminish Melville's popularity during his lifetime is the one for which he is best known today.
3. In what year did Melville's book about his experiences as a cabin boy appear?

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Sylvia Plath’s semi-autobiographical 1963 book “The Bell Jar” is most likely to be found in a sophomore English class, pored over by high-school students. But recently at Squarefoot, a commercial real estate company based in Manhattan, it was the chosen book title for the office book club. “People really latched onto [“The Bell Jar”] and talked about women’s roles in the workplace,” says Eliza Bell, people-operations manager. “The book club has been a bonding opportunity. People are able to learn about each other, and it’s really nice to talk about stuff that isn’t work-related. ‘The Bell Jar’ really brought that out, and we were able to talk about diversity initiatives.” Over the summer, the book pick was “The Hate U Give,” the 2017 young adult novel by Angie Thomas. The monthly club meets during a lunch that is provided by the company. In its first iteration, the club met after work and read business books: Not surprisingly, people weren’t quite as enthusiastic about that initiative. The club is the brainchild of CEO Jonathan. Wasserstrum, who is passionate about reading. There are some rules: At the beginning everyone has a chance to express what they liked or didn’t like. “If someone goes on a rant, it’s important to change the topic and move to another one,” says Bell. “When we read ‘The Last Lecture’ [the 2008 bestseller co-authored by the late Randy Pausch] for instance, it got a little heated.” What makes for a good pick? “We need an aspect of it to get people excited. It’s important that the books are ones people will have opinions on. People can learn from all sorts of different books,” says Bell. “And they have to be less than 250 pages.”  
5. The word “they” in paragraph 3 refers to _______

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A group of Tri-City residents and volunteers from BC Housing gathered at a  neglected therapeutic garden on the old Riverview Hospital grounds last weekend to breathe life into a green space. First planted by psychiatric nurse Art Finnie in the 1950s after he was injured on the job, Finnie’s Garden grew into one of the first experiments in horticultural  therapy. As Lauren English, director of land development for Riverview, put it, gardening as therapy was a revolutionary practice. “He understood the value of nature and how therapeutic it was before it became the rage — to find peace and to find solace and to find comfort,” added MLA Selina Robinson, who attended last Saturday’s event.  At that time, Riverview Hospital was the largest psychiatric hospital in British Columbia, with more than 5,000 patients on site. And Finnie’s was more than a garden. Beyond the rows of corn, flowers and a fish pond, residents could lounge in a picnic area or curve bowls across their own bowling green. But while the idea of Finnie’s Garden was to have a place of gathering that residents created themselves, they weren’t the first ones to make themselves at home.  Archeologists, including one on site last weekend, have found evidence Indigenous people occupied the area for thousands of years. Today, the Kwikwetlem First Nation maintains a land claim over the Riverview lands, and in its language, the area is known as Smu’q wa ala," or “Place of the Great Blue Heron”. "They found fire-altered rocks, they found boiling rocks, they found arrowheads, they found tools," said English, under the watchful eye of the group’s archeologist. “It’s not just colonial history, it’s the precontact history that goes back thousands of years.” Today, while many of the former hospital’s buildings lay in disrepair, 184 people still call the hilltop facility home, and one day in the near future, perhaps, they’ll get to use it again on their road to recovery. The event comes in a year when Treefest was cancelled because of a lack of organizers, and while the renewed work at Finnie’s Garden isn’t meant to replace Treefest, it does offer a outlet for green-thumbs without a patch of dirt.  A final community gardening event at Finnie’s Garden will likely take place in October. By removing weeds, invasive plants and adding mulch, the group plans to have the area ready to plant next spring. 
3. According to paragraph 1, what kind of therapeutic effects does Finnie’s Garden serve? 

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Just as optical fibers have transformed communication, they are also revolutionizing medicine. These ultra - thin, flxible fiers have opened a window into the living tissues of the body. By inserting optical fibers through natural openings or small incisions and the threading them along the body's established pathways, physicians can look into the lungs, intestines, heart and other areas that were formerly inaccessible to them. The basic fiber-optics system is called fiberscope, which consists of two bundles of fibers. One, the illuminating bundle, carries light to the tissues. It is coupled to a high-intensity light source. Light enters the cores of the high-purity silicon glass and travels along the fibers. A lens at the end of the bundle collects the light and focuses it into the other bundle, the imaging bundle. Each fibers in the bundle transmits only a tiny fraction of the total image. The reconstructed image can be viewed through an eyepiece or displayed on a television screen. During the last five years, improved methods of fabricating optical fibers have led to a reduction in fiberscope diameter and an increase in the number of fibers, which in turn has increased resolution. Optical fibers can also be used to deliver laser light. By use of laser beams, physicians can perform surgery inside the body, sometimes eliminating the need of invasive procedures in which healthy tissue must be cut through to reach the site of disease. Many of these procedures do not require anesthesia and can be performed in a physician's office. These techniques have reduced the risk and the cost of medical care.
6. Which of the following is closest in meaning to the word "cores"?

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Leonardo da Vinci was born on April 15, 1452, in the small Tuscan town of Vinci,  near Florence. Leonardo was the son of a wealthy Florentine public official and a peasant woman. In the mid- 1460s, the family settled in Florence, where Leonardo was given the best education that Florence could offer. He rapidly advanced socially and intellectually. He was handsome, persuasive in conversation and a fine musician and improviser. About in 1466, he apprenticed as a studio boy to Andrea Del Verrocchio. In Verrocchio’s workshop, Leonardo was introduced to many activities, from the painting of altarpieces and panel pictures to the creation of large sculptural projects. In 1472, he was entered in the painter’s guild of Florence, and in 1476, he was still mentioned as Verrocchio’s assistant. In Verrocchio’s Baptism of Christ, the kneeling angel at the left of the painting is by Leonardo.  In 1478, Leonardo became an independent master. His first commission, to paint an altarpiece for the chapel of the Palazzo Vecchino, the Florentine town hall, was never executed. His first large painting, The Adoration of the Magi, left unfinished, was ordered in 1481 for the Monastery of San Donato a Scopeto, Florence. Other works ascribed to his youth are the so-called Benois Madonna, the portrait Ginerva de’ Benci, and the unfinished Saint Jerome.  In 1482, Leonardo’s career moved into high gear when he entered the service of the duke of Milan, Ludovico Sforza, having written the duke an astonishing letter in which he stated that he could build portable bridges; that he knew the techniques of constructing bombardments and of making cannons; that he could build ships as well as armored vehicles, catapults, and other war machines; and that he could execute sculpture in marble, bronze, and clay. He served as a principal engineer in the duke’s numerous military enterprises and was so active also as an architect. In addition, he assisted the Italian mathematician Luca Pacioli in the celebrated work Divina Proportione.  Evidence indicates that Leonardo had apprentices and pupils in Milan, for whom he probably wrote the various texts later compiled as Treatise on Painting. The most important of his own paintings during the early Milan period was The Virgin of the Rocks, two versions of which exist; he worked on the compositions for a long time, as was his custom, seemingly unwilling to finish what he had begun.  From 1495 to 1496, Leonardo labored on his masterpiece, The Last Super, a mural in the refectory of the Monastery of Santa Maria Delle Grazie, Milan. Unfortunately, his experimental use of oil on dry plaster was technically unsound, and by 1500 its deterioration had begun. Since 1726 attempts have been made, unsuccessfully, to restore it; a concerted restoration and conservation program, making use of the latest technology, was begun in 1977 and is reversing some of the damage. Although much of the original surface is gone, the majesty of the composition and the penetrating characterization of the figures give a fleeting vision of its vanished splendor.  During his long stay in Milan, Leonardo also produced other paintings and drawings, most of which have been lost theater designs, architectural drawings, and models for the dome of Milan Cathedral. His largest commission was for a colossal bronze monument to Francesco Sforza, father of Ludovico, in the courtyard of Castello Sforzesco. In December 1499, however, the Sforza family was driven from Milan by French forces; Leonardo left the statue unfinished and he returned to Florence in 1500.
2. How old was Leonardo da Vinci when he became an independent master?