Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:
Our eyes and ears might be called transformers because they send the light and sound around us and turn them into electrical impulses that the brain can interpret. These electrical impulses that have been transformed by the eyes and ears reach the brain and are turned into massages that we can interpret. For the eye, the process begins as the eye admits light waves, bends them at the cornea and lens, and then focuses them on the retina. At the back of each eye, nerve fibers bundle together to form optic nerves, which join and then split into optic tracts. Some of the fibers cross so that part of the input from the right visual field goes into the left side of the brain, and vice versa. The process in the ear is carried out through sensory cells that are carried in fluid-filled canals and that are extremely sensitive to vibration. Sound that is transformed into electricity travels along nerve fibers in the auditory nerve. These fibers form a synapse with neurons that carry the massages to the auditory cortex on each side of the brain.

According to the author, we might call our eyes and ears "transformers" because     .

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:
The ocean bottom - a region nearly 2.5 times greater than the total land area of the Earth - is a vast frontier that even today is largely unexplored and uncharted. Until about a century ago, the deep ocean floor was completely inaccessible, hidden beneath waters averaging over 3,600 meters deep. Totally without light and subjected to intense pressures hundreds of times greater than at the Earth's surface, the deep-ocean bottom is a hostile environment to humans, in some ways as forbidding and remote as the void of outer space.
Although researchers have taken samples of deep-ocean rocks and sediments for over a century, the first detailed global investigation of the ocean bottom did not actually start until 1968, with the beginning of the National Science Foundation's Deep Sea Drilling Project (DSDP). Using techniques first developed for the offshore oil and gas industry, the DSDP's drill ship, the Glomar Challenger, was able to maintain a steady position on the ocean's surface and drill in very deep waters, extracting samples of sediments and rock from the ocean floor.
The Glomar Challenger completed 96 voyages in a 15-year research program that ended in November 1983. During this time, the vessel logged 600,000 kilometers and took almost 20,000 core samples of seabed sediments and rocks at 624 drilling sites around the world. The Glomar Challenger's core samples have allowed geologists to reconstruct what the planet looked like hundreds of millions of years ago and to calculate what it will probably look like millions of years in the future. Today, largely on the strength of evidence gathered during the Glomar Challenger's voyages, nearly all earth scientists agree on the theories of plate tectonics and continental drift that explain many of the geological processes that shape the Earth.
The cores of sediment drilled by the Glomar Challenger have also yielded information critical to understanding the world's past climates. Deep-ocean sediments provide a climatic record stretching back hundreds of millions of years, because they are largely isolated from the mechanical erosion and the intense chemical and biological activity that rapidly destroy much land-based evidence of past climates. This record has already provided insights into the patterns and causes of past climatic change - information that may be used to predict future climates.

The deep Sea Drilling Project was significant because it was    .

Choose the word or phrase that best fits each space in the following passage

 Many people love boats. Going out on the water on a warm summer day is a lot of fun. (1) _______ ,different people like different kinds of boats. Two of the most popular kinds of boat are sailboats and speedboats. Sailboats use the (2) _______to give them power. They only have small engines. In contrast, speedboats have large engines and go very fast. Furthermore, speedboats are usually not as (3) _______ as sailboats. Speedboats are small so that they can go fast. Sailboats, on the other hand, are big so that they are more comfortable. ( 4) _______, sailboats can travel into the ocean, but this would be very dangerous in a speedboat. You can only use speedboats on rivers or lakes.

(2) _______

Choose the letter A, B, C or D to answer these following questions

According to futurist Ray Kurzweil human civilisation will be unavoidably transformed in the year 2045 by an event that he call The Singularity. He suggests that exponential technological development will lead to the inevitable rise of artificial intelligence (A.I.). Such advanced technology may make humanity insignificant.

Kurzweil says that technologies are double-edged swords and envisions the possibility that an artificial intelligence might decde to put an end to humanity simply because it surpasses human intelligence. Kurzweil does have faith in mankind, however. He suggests that people are wise to accept that technological progress is unavoidable and that such acceptance will make the process of transition easier.

Kurzweil has personal reasons to hope for the coming of The Singularity, because he wants his life to be extended by it. Kurzweil envisions that future medical advances could invent tiny computerised machines, or nanobots, which operate inside the body to enhance the immune system. In addition ne believes that future technology might be able to resurrect his deceased father.

Looking at the state of current technological advances in many fields such as medicine, navigation and communication, Kurzweil's visions may not be unbelievable.The critical issue, however, is whether genuine artificial intelligence can ever be truly realised. Kurzweil suggests that critics of his theories, who believe that the human brain is too complex to duplicate, are underestimating what the exponential growth in technology can eventually accomplish.

Why could The Singularity put an end to humans?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:
Reality television is genre of television programming which, (it is claimed), presents unscripted dramatic or humorous situation, documents actual events, and features ordinary rather than professional actors. It could be described as a form of artificial or “heightened” documentary. Although the genre has existed in some form or another since the early years of television, the current explosion of popularity dates from around 2000.
Reality television covers a wide range of television programming formats, from game or quiz shows which resemble the frantic, often demeaning programmes produced in Japan in the 1980s and 1990s (a modem example is Gaki no Tsukai), to surveillance- or voyeurism- focused productions such as Big Brother.
Critics say that the term “reality television” is somewhat of a misnomer and that such shows frequently portray a modifies and highly influenced form of reality, with participants put in exotic location or abnormal situations, sometimes coached to act in certain ways by off-screen handlers, and with events on screen manipulated through editing and other post-production techniques.
Part of reality television’s appeal is due to its ability to place ordinary people in extraordinary situations. For example, on the ABC show, The Bachelor, an eligible male dates a dozen women simultaneously, traveling on extraordinary dates to scenic locales. Reality television also has the potential to turn its participants into national celebrities, outwardly in talent and performance programs such as Pop Idol, though frequently Survivor and Big Brother participants also reach some degree of celebrity.
Some commentators have said that the name “reality television” is an inaccurate description for several styles of program included in the genre. In competition- based programs such as Big Brother and Survivor, and other special-living-environment shows like The Real World, the producers design the format of the show and control the day-to-day activities and the environment, creating a completely fabricated world in which the competition plays out. Producers specifically select the participants, and use carefully designed scenarios, challenges, events, and settings to encourage particular behaviours and conflicts. Mark Burnett, creator of Survivor and other reality shows, has agreed with this assessment, and avoids the word “reality” to describe his shows; he has said, “I tell good stories. It really is not reality TV. It really is unscripted drama.”

The term “reality television” is inaccurate ..................

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions:
What unusual or unique biological train led to the remarkable diversification and unchallenged success of the ants for over 50 million years? The answer appears to be that they were the first group of predatory eusocial insects that both lived and foraged primarily in the soil and in rotting vegetation on the ground. Eusocial refers to a form of insect society characterized by specialization of tasks and cooperative care of the young; it is rare among insects. Richly organized colonies of the land made possible by eusociality enjoy several key advantages over solitary individuals.
Under most circumstances groups of workers are better able to forage for food and defend the nest, because they can switch from individual to group response and back again swiftly and according to need. When a food object or nest intruder is too large for one individual to handle, nestmates can be quickly assembled by alarm or recruitment signals. Equally important is the fact that the execution of multiple- step tasks is accomplished in a series-parallel sequence. That is, individual ants can specialize in particular steps, moving from one object (such as a larva to be fed) to another (a second larva to be fed). They do not need to carry each task to completion from start to finish - for example, to check the larva first, then collect the food, then feed the larva. Hence, if each link in the chain has many workers in attendance, a sense directed at any particular object is less likely to fail. Moreover, ants specializing in particular labor categories typically constitute a caste specialized by age or body form or both. There has been some documentation of the superiority in performance and net energetic yield of various castes for their modal tasks, although careful experimental studies are still relatively few.

What makes ants unusual in the company of eusocial insects is the fact that they are the only eusocial predators (predators are animals that capture and feed on other animals) occupying the soil and ground litter. The eusocial termites live in the same places as ants and also have wingless workers, but they feed almost exclusively on dead vegetation.

The task of feeding larvae is mentioned in the passage to demonstrate     .

Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for people to communicate larger amounts of information between two places. The telegram and telephone set the stage for more modern means of communication. With the invention of the cellular phone, communication itself has become mobile.
For you, a cell phone is probably just a device that you and your friends use to keep in touch with family and friends, take pictures, play games, or send text message. The definition of a cell phone is more specific: it is a hand- held wireless communication device that sends and receives signals by way of small special areas called cells.
Walkie - talkies, telephones and cell phones are duplex communication devices: They make it possible for two people to talk to each other. Cell phones and walkie- talkies are different from regular phones because they can be used in many different locations. A walkie- talkie is sometimes called a half- duplex communication device because only one person can talk at a time. A cell phone is a full- duplex device because it uses both frequencies at the same time. A walkie-talkie has only one channel. A cell phone has more than a thousand channels. A walkie- talkie can transmit and receive signals across a distance of about a mile. A cell phone can transmit and receive signals over hundreds of miles. In 1973, an electronic company called Motorola hired Martin Cooper to work on wireless communication. Motorola and Bell Laboratories (now AT& T) were in a race to invent the first portable communication device.
Martin Cooper won the race and became the inventor of the cell phone. On April 3, 1973, Cooper made the first cell phone call to his opponent at AT& T while walking down the streets of New York city. People on the sidewalks gazed at cooper in amazement. Cooper's phone was called A Motorola Dyna- Tac. It weighed a whopping 2.5 pounds (as compared to today's cell phones that weigh as little as 3 or 4 ounces)
After the invention of his cell phone, Cooper began thinking of ways to make the cell phone available to the general public. After a decade, Motorola introduced the first cell phone for commercial use. The early cell phone and its service were both expensive. The cell phone itself cost about $ 3, 500. In 1977, AT & T constructed a cell phone system and tried it out in Chicago with over 2, 000 customers. In 1981, a second cellular phone system was started in the Washington,D.C and Baltimore area. It took nearly 37 years for cell phones to become available for general public use. Today, there are more than sixty million cell phone customers with cell phones producing over thirty billion dollars per years.

To whom did Cooper make his first cell phone call?

The protozoans, minute, aquatic creatures each of which consists of a single cell of protoplasm, constitute a classification of the most primitive forms of animal life. They are fantastically diverse, but three major groups may be identified on the basis of their motility. The Mastigophora have one or more long tails, which they use to project themselves forward. The Ciliata, which use the same basic means for locomotion as the Mastigophora, have a larger number of short tails. The Sarcodina, which include amoebae, float or row themselves about on their crusted bodies.
In addition to their form of movement, several other features discriminate among the three groups of protozoans. For example, at least two nuclei per cell have been identified in the Ciliata, usually a large nucleus that regulates growth but decomposes during reproduction, and a smaller one that contains the genetic code necessary to generate the large nucleus.
Protozoans are considered animals because, unlike pigmented plants to which some protozoans are otherwise almost identical, they do not live on simple organic compounds. Their cell demonstrates all of the major characteristics of the cells of higher animals.
Many species of protozoans collect into colonies, physically connected to each other and responding uniformly to outside stimulate. Current research into this phenomenon, along with investigations carried out with advanced microscopes may necessitate a redefinition of what constitutes protozoans, even calling into question the basic premise that they have only one cell. Nevertheless, with the current data available, almost 40,000 species of protozoans have been identified. No doubt, as the technology improves our methods of observation, better models of classification will be proposed.

To which class of protozoans do the amoebae belong?

It's called 42 - the name taken from the answer to the meaning of life, from the science fiction series The Hitchhiker's Guide to the Galaxy. 42 was founded by French technology billionaire Xavier Niel, whose backing means there are no tuition fees and accommodation is free. Mr Niel and his co-founders come from the world of technology and start-ups, and they are trying to do to education what Facebook did to communication and Airbnb to accommodation.
Students at 42 are given a choice of projects that they might be set in a job as a software engineer - perhaps to design a website or a computer game. They complete a project using resources freely available on the Internet and by seeking help from their fellow students, who work alongside them in a large open-plan room full of computers. Another student will then be randomly assigned to mark their work.
The founders claim this method of learning makes up for shortcomings in the traditional education system, which they say encourages students to be passive recipients of knowledge. "Peer-to-peer learning develops students with the confidence to search for solutions by themselves, often in quite creative and ingenious ways."
Like in computer games, the students are asked to design and they go up a level by completing a project. They graduate when they reach level 21, which usually takes three to five years. And at the end, there is a certificate but no formal degree. Recent graduates are now working at companies including IBM, Amazon, and Tesla, as well as starting their own firms.
"The feedback we have had from employers is that our graduates are more apt to go off and find out information for themselves, rather than asking their supervisors what to do next," says Brittany Bir, chief operating officer of 42 in California and a graduate of its sister school in Paris. Ms Bir says 42's graduates will be better able to work with others and discuss and defend their ideas - an important skill in the “real world” of work. "This is particularly important in computer programming, where individuals are notorious for lacking certain human skills," she says. 
But could 42's model of teacher less learning work in mainstream universities? Brittany Bir admits 42's methods do not suit all students. "It suits individuals who are very disciplined and self-motivated, and who are not scared by having the freedom to work at their own pace," she says.

The word “them” in paragraph 2 refers to ..........

It was the first photograph that I had ever seen, and it fascinated me. I can remember holding it at every angle in order to catch the flickering light from the oil lamp on the dresser. The man in the photograph was unsmiling, but his eyes were kind. I had never met him, but I felt that I knew him. One evening when I was looking at the photograph, as I always did before I went to sleep, I noticed a shadow across the man’s thin face. I moved the photograph so that the shadow lay perfectly around his hollow cheecks. How different he looked!
That night I could not sleep, thinking about the letter that I would write. First, I would tell him that I was eleven years old, and that if he had a little girl my age, she could write to me instead of him. I knew that he was a very busy man. Then I would explain to him the real purpose of my letter. I would tell him how wonderful he looked with the shadow that I had seen across his photograph, and I would most carefully suggest that he grow whiskers.
Four months later when I met him at the train station near my home in Westfield, New York, he was wearing a full beard. He was so much taller than I had imagined from my tiny photograph.
“Ladies and gentlemen,” he said, “I have no speech to make and no time to make it in. I appear before you that I may see you and that you may see me.” Then he picked me right up and kissed me on both cheeks. The whiskers scratched. “Do you think I look better, my little friend?” he asked me.
My name is Grace Bedell, and the man in the photograph was Abraham Lincoln.

The word “fascinated” in paragraph 1 could best be replaced by.........

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:
Fifty-five delegates representing all thirteen states except Rhode Island attended the Constitutional Convention in Philadelphia from May to September 1787. The delegates had been instructed by the Continental Congress to revise the old Articles of Confederation, but most believed that a stronger central government was needed. There were differences, however, about what structure the government should take and how much influence large states should have.
Virginia was by far the most populous state, with twice as many as people as New York, four times as many as New Jersey, and ten times as many as Delaware. The leader of the Virginia delegation, James Madison, had already drawn up a plan for government, which became known as the Large State Plan. Its essence was that congressional representation would be based on population. It provided for two or more national executives. The smaller states feared that under this plan, a few large states would lord over the rest. New Jersey countered with the Small State Plan. It provided for equal representation for all states in a national legislature and for a single national executive. Angry debate, heightened by a stifling heat wave, led to deadlock.
A cooling of tempers seemed to come with lower temperatures. The delegates hammered out an agreement known as the Great Compromise- actually a bundle of shrewd compromises. They decided that Congress would consist of two houses. The larger states were granted representation based on population in the lower house, the House of Representatives. The smaller states were given equal representation in the upper house, the Senate, in which each state would have two senators regardless of population. It was also agreed that there would be a single executive, the president. This critical compromise broke the logjam, and from then on, success seemed within reach.

According to the passage, in 1787 which of the following states had FEWEST people?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:
A gesture is an action that sends a message from one person to another without using words. We use gestures to communicate with others. There are some gestures that have completely different meaning depending on when and where they are used.
When an American wants to show that something is OK. or good, he raises his hand and makes a circle with his thumb and foreigners. The circle sign has only one meaning for him. He might be surprised to learn that in other countries it can mean something different. In Japan, for instance, it is the gesture for money. In France, it means 'zero' or 'worthless'. Such differences can lead to all kinds of misunderstanding when foreigners meet. But why is it that the same gesture has so many different meanings?
When some people want to show that something is exact or precise, they make a sign to show that they are holding something between the tips of their thumb and forefinger. Many people from all over the world do this when they want to make a specific point as they are speaking. People later started using this signal to mean 'exactly right' or 'perfect'. This was how the famous OK was bom.
In Japan, money means coins and coins are around. Therefore, making a round hand sign came to represent money. It is simple as that. The French sign for 'nothing' or 'worthless' also has a simple origin. This time the circle doesn't represent a coin, but nought. Nought equals zero, zero equals nothing, nothing equals worthless.

The word "they" in paragraph 3 refers to ..................

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks.
 In recent years there have been many articles on air pollution in newspapers and magazines. Scientists all over the world have warned that our atmosphere is (1).....more and more contaminated, and that Man, through his carelessness, may run out of pure air to breathe.
Automobiles and industries mainly account (2).... air pollution in most cities. They pour into the air such gases as carbon monoxide, sulfur and nitrogen oxides, (3)...... are very harmful to humans. (4)......still, these gases, a series of chemical changes, turn into toxic acids. They fall down in “acid rains”, raising the acidity in the air, soil and water to dangerous levels and affecting not only tress but also fish and other wildlife. Many industrial countries in Europe and North America have suffered bad effects (5)......those “rains”.
Surely, Man faces no more urgent problem than that of saving his own survival. Scientists, social organizations and governments shout sit down together to solve the air pollution problem.
(1).........................

Interest is the sum charged for borrowing money for a fixed period of time. Principal is the term used for the money that is borrowed, and the rate of interest is the percent per year of the principal charged for its use. Most of the profits for a bank are derived from the interest that they charge for the use of their own or their depositor’s money.
All problems in interest may be solved by using one general equation that may be stated as follows:
Interest = Principal X Rate X Time
Any one of the four quantities – that is, interest, principal, rate, or time – may be found when the other three are known. The time is expressed in years. The rate is expressed as a decimal fraction. Thus, 6 percent interest means six cents charged for the use of $1 of principal borrowed for one year. Although the time may be less than, equal to, or greater than one year, most applications for loans are for periods of less than one year. For purpose of computing interest for short periods, the commercial year or 360 days is commonly used, but when large sums of money are involved, exact interest is computed on the basis of 365 days.

The word “fixed” in paragraph 1 is closest in meaning to..........

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:
In Viet Nam festivals often take place during the three months in spring and in autumn when people have a lot of leisure time. In addition, the climate in spring and autumn is especially suitable for holding festivals and for festivals goers to enjoy. Traditional festivals constitute a form of cultural activities, a spiritual product which the people have created and developed during the course of history. From generation to generation, the Vietnamese people preserve the fine tradition of “remembering the source while drinking water.” Festivals are events which represent this tradition of the community as well as honour the holy figures named as “gods” -the real persons in national history or legendary persons. The images of gods converge the noble characteristics of mankind. They are national heroes who fought against foreign invaders, reclaimed new lands, treated people, fought against natural calamities, or those legendary characters who affect the earthly life.
Accordingly, first and foremost, festivals are events when people pay tribute to divinities that rendered merits to the community and the nation. These are occasions when people come back to either their natural or national roots, which form a sacred part in their mind. Furthermore, testivals represent the strength of the commune or village, the local region or even the whole nation. Worshipping the same god, the people unite in solidarity to overcome difficulties, striving for a happy and wealthy life.
Moreover, festivals display the demand for creativity and enjoyment of spiritual and material cultural values of all social strata. They become a form of education under which fine traditional moral values can be handed from one generation to the next in a unique way of combining spiritual characters with competition and entertainment games. Festivals are also the time people can express their sadness and worries in a wish that gods might bestow favour on them to help them strive for a better life.

Which of the followings best replace the word “course” in the second paragraph?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:
“ Calcite- containing dust particles blow into the air and combine with nitric acid in polluted air from factories to form an entirely new particle – calcium nitrate , ” said Alexander Laskin, a senior research scientist at the Department of Energy’s Pacific Northwest National Laboratory in Richland, Washington .These nitrates have optical and chemical properties that are completely different from those of the originally dry dust particles . Due to this, climate models need to be updated to reflect this chemistry. Calcite dust is common in arid areas such as Israel, where scientists collected particles for analysis.
Working from a mountaintop, the team collected dust that had blown in from the northern shores of Egypt, Sinai,and southern Israel. The particles had combined with air containing pollutants that came from Cairo.They analyzed nearly 2,00 individual particles and observed the physical and chemical changes at the W.R Wiley Environmental Sciences Laboratory.
A key change in the properties of the newly formed nitrate particles is that they begin to absorb water and retain the moisture .These wet particles can scatter and absorb sunlight-presenting climate modelers, who need to know where the energy is going , a new wild card to deal with . Companion studies of dust samples from the Sahara and the Saudi coast and loess from China show that the higher the calcium in the mineral , the more reactive they are in with nitric acid .And once the particle is changed , it stays that way.
“When dust storms kick up these particles and they enter polluted areas , the particles change ,” Laskin said . “To what extent this is happening globally, as more of the world becomes industrialized , we don’t know . But now we have the laboratory and field evidence that shows it is definitely happening . The story is much more complicated than anybody thought .”

Why do climate models need to be updated to reflect the chemistry of calcium nitrate ?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.
A healthy way to know a city Maybe you are staying in a city, and there is no park nearby where you can take your morning job. One of the more recent trend is to go on a running tour, but you are not leading the way. Rather, a running enthusiast (1).......   knows the best (2)..... in the city acts as your guide. You are going out for a run, but you are also being shown highlights of the city while you are doing it.
Guided running tours are a trend that seems to be catching (3)...... in quite a few of the bigger cities in the United States. New York City, Chicago, and San Francisco are just three of the major cities that  have  running  tours in (4)........... They offer these tours to individuals, groups, and even for corporate events. If you are going into a city with colleagues to attend a business meeting or a convention, what better way is there to see the city and network with others (5) .......while taking a healthy run? 
(3).......................................

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.
         The Robots Are Doing the Thinking
Some robots may take care of the dishes, do your laundry, keep the house clean, or even go to the store to do your shopping. Robots that use artificial intelligence are the ones that a lot of people are holding out for. Not only will these robots be able to take care of (1)....... , but they will be able to learn as well.
There are some types of roots that already use a form of artificial intelligence called swarm intelligence. As a(n) (2) ........... of how this works, scientists have create underwater roots that will be used to repair coral reefs that have been damaged. What these robots do is work together to rebuild damaged reefs. As they (3)........ , each one knows what has been done in one area of a reef and can help build other areas or build onto something that another robot has done. Working together, the robots create a new reef that can then be (4)............to grow and thrive on its own. Amazon, the major electronic commerce company, has recently come (5).......an ingenious idea. Instead of having a package delivered to a customer via delivery truck, Amazon will send out lying drones that ill ring a package to a person’s house or delivery almost immediately.
(1)................................

The attraction of gold is as old as history. Since ancient times, gold has been the object of dreams and obsessions. Western literature is full of characters who kill for gold or hoard it, from King Midas in the ancient Greek myths, to Fagin in Dickens' Oliver Twist. These characters go to evil extremes to get or keep their gold and they get the punishment they deserve. Most people would not be willing to go to such extremes, of course, but they would not question the assumption that gold has lasting value above and beyond any local currency. Societies change over time, customs and currencies evolve, but gold remains. A wedding ring, for example, must be gold, and so should any serious gift of jewelry. In fact, giving and wearing gold is still a mark of prestige in our post-industrial society, though gold is no longer valued as it used to be thousands of years ago.
Why is gold so valuable? True, it is shiny, durable, and rare, but it is far less useful than many other minerals or metals. It is also not like stock in a company, where the value of the stock depends on the performance of the company. Gold, on the contrary, like any currency, is valuable precisely because people believe it is valuable. That is, if people were willing to accept seashells for their labor and could use them to pay for food, fuel, and other commodities, then seashells would become a valuable currency. Thus, the value of gold depends on the collective belief that gold will continue to be valuable. As long as demand for gold remains steady, the price will hold steady; if demand is high, it will continue to increase in value. But if people should someday lose faith in gold, the price of gold could fall sharply.
Another factor that has affected the price of gold has been the increasing difficulty in acquiring it. Today, most of the gold left in the grounds is in microscopic pieces mixed with rock. To get it, miners must dig up tons and tons of rock, and then spray it with chemicals to separate out the gold. For one ounce of gold - a wedding ring, for example - the mine processes about 30 tons of rock. This is already a costly operation. But there are also hidden social and environmental costs. The mining and processing of gold is ruinous to the environment and to the health of people living nearby. Most of these mines are in poor regions where the people have had little voice in whether there should be mines and how the mines should be run. The large multinational mining companies simply bought the land and opened the mines. However, as people and governments begin to realize the extent of the damage caused by the mines, the situation might change.
Indeed, if the mining companies ever have to pay the full environmental and social costs of mining gold, the price of gold is likely to climb yet higher.

Which of the following does author most probably agree with?

Increasing numbers of parents in the U.S. are choosing to teach their children at home. In fact, the U.S. Department of Education has estimated that in 1999, about 850,000 children were being homeschooled. Some educational experts say that the real number is double this estimate, and the ranks of homeschooled children seem to be growing at the average rate of about eleven percent every year.
At one time, there was a theory accounting for homeschooling: it was traditionally used for students who could not attend school because of behavioral or learning difficulties. Today, however, more parents are taking on the responsibility of educating their own children at home due to their dissatisfaction with the educational system. Many parents are unhappy about class size, as well as problems inside the classroom. Teacher shortages and lack of funding mean that, in many schools, one teacher is responsible for thirty or forty students. The children are, therefore, deprived of the attention they need. Escalating classroom violence has also motivated some parents to remove their children from school.

Although there have been a lot of arguments for and against it, homeschooling in the U.S. has become a multi-million dollar industry, and it is growing bigger and bigger. There are now plenty of websites, support groups, and conventions that help parents protect their rights and enable them to learn more about educating their children. Though once it was the only choice for troubled children, homeschooling today is an accepted alternative to an educational system that many believe is failing.

The past participle “homeschooled” in the first paragraph is best equivalent to “_ at home”