Read the following passage and choose the best answer (A, B, C, D):
The United Nations is an international organization founded in 1945. It is currently made up of 193 member countries. Its main goal is to bring different nations together to promote peace and justice in the world. The UN also works to make the world a safe and secure place. It is important to remember that the UN is not a “world government”. This means that the UN does not make laws for different countries to follow. However, the UN does hold regular votes on global policies and issues. The main branch of the UN is called the “General Assembly”. All members of the United Nations are represented and have their votes. If there is a problem in a certain area of the world or a particular country, the UN will vote on how to best solve the problem. At least two-thirds of all member countries must agree on how to resolve the problem in order for the UN to take action. If less than two-thirds of the voting countries agree, no immediate action is taken. Another branch is the Security Council. Its main purpose is to maintain international peace and keep the world secure. This branch has only fifteen members, five of which are permanent, including China, France, Russia, the United Kingdom, and the United States. The other ten members are elected by the General Assembly for two-year terms. IF the council feels that international peace is being threatened, the fifteen members will try to outline a way to resolve the situation in a peaceful manner. The third important branch is the Economic and Social Council. This branch works to help monitor the world economy and resolve social issues around the world such as violations of human rights, the fight against international crime and destruction of the environment. There are 54 government representatives serving on this council. They are elected by the General Assembly to serve for three-year terms. Council members are elected to represent certain areas of the world. 
4. The UN is called an international organization because: 

Read the passage carefully, then choose the correct answers.

Having a best friend to confide in can bring a positive effect on our emotional health. An evening out with the closest friend may be the best guarantee of a good time. In fact, our best friend can prevent us from developing serious psychological problems such as depression and anxiety.

Best friendship evolves with time - we cannot go out and pick our best friend. We become friends with people who share common interests – at school or through hobbies, for example.

Best friends have usually known each other for years and stuck together through good and bad times. If you haven't got one, perhaps you are being too distant from people, or focusing too much on your work.

 The word 'one' in the last paragraph refers to ________.

By the mid-nineteenth century, the term "icebox" had entered the American language, but ice was still only beginning to affect the diet of ordinary citizens in the United States. The ice trade grew with the growth of cities. Ice was used in hotels, taverns, and hospitals, and by some forward-looking city dealers in fresh meat, fresh fish, and butter. After the Civil War (1860-1865), as ice was used to refrigerate freight cars, it also came into household use. Even before 1880, half the ice sold in New York, Philadelphia, and Baltimore, and one-third of that sold in Boston and Chicago, went to families for their own use. This had become possible because a new household convenience, the icebox, a precursor of the modern refrigerator, had been invented.
 Making an efficient icebox was not as easy as we might now suppose. In the early nineteenth century, the knowledge of the physics of heat, which was essential to a science of refrigeration, was rudimentary. The common-sense notion that the best icebox was one that prevented the ice from melting was of course mistaken, for it was the melting of the ice that performed the cooling. Nevertheless, early efforts to economize ice included wrapping the ice in blankets, which kept the ice from doing its job. Not until near the end of the nineteenth century did inventors achieve the nice balance of insulation and circulation needed for an efficient icebox.
 But as early as 1803, an ingenious Maryland farmer, Thomas Moore, had been on the right track. He owned a farm about twenty miles outside the city of Washington, for which the village of Georgetown was the market center. When he used an icebox of his own design to transport his butter to market, he found that customers would pass up the rapidly melting stuff in the tubs of his competitors to pay a premium price for his butter, still fresh and hard in neat, one-pound bricks. One advantage of his icebox, Moore explained, was that farmers would no longer have to travel to market at night in order to keep their produce cool.

What does the passage mainly discuss?

Read the following passage and choose the best answer (A, B, C, D):
A survey is a study, generally in the form of an interview or a questionnaire, which provides information concerning how people think and act. In the United States, the best-known surveys are the Gallup poll and the Harris poll. As anyone who watches the news during campaigns presidential knows, these polls have become an important part of political life in the United States.
North Americans are familiar with the many “person on the street” interviews on local television news shows. While such interviews can be highly entertaining, they are not necessarily an accurate indication of public opinion. First, they reflect the opinions of only those people who appear at a certain location. Thus, such samples can be biased in favor of commuters, middle-class shoppers, or factory workers, depending on which area the news people select. Second, television interviews tend to attract outgoing people who are willing to appear on the air, while they frighten away others who may feel intimidated by a camera. A survey must be based on a precise, representative sampling if it is to genuinely reflect a broad range of the population.
In preparing to conduct a survey, sociologists must exercise great care in the wording of questions. An effective survey question must be simple and clear enough for people to understand it. It must also be specific enough so that there are no problems in interpreting the results. Even questions that are less structured must be carefully phrased in order to elicit the type of information desired. Surveys can be indispensable sources of information, but only if the sampling is done properly and the questions are worded accurately.
There are two main forms of surveys: the interview and the questionnaire. Each of these forms of survey research has its advantages. An interviewer can obtain a high response rate because people find it more difficult to turn down a personal request for an interview than to throw away a written questionnaire. In addition, an interviewer can go beyond written questions and probe for a subject’s underlying feelings  and reasons. However, questionnaires have the advantage of being cheaper and more consistent.
1. What does the passage mainly discuss?

Read the following passage and choose the best answer (A, B, C, D):
Music can bring US to tears or to our feet, drive US into battle or lull US to sleep. Music is indeed remarkable in its power over all humankind, and perhaps for that every reason, no human culture on earth has ever lived without it. From discoveries made in France and Slovenia even Neanderthal man, as long as 53,000 years ago, had developed surprisingly sophisticated, sweet-sounding flutes carved from animal bones. It is perhaps then, no accident that music should strike such a chord with the limbic system - an ancient part of our brain, evolutionarily speaking, and one that we share with much of the animal kingdom. Some researchers even propose that music came into this world long before the human race ever did. For  example, the fact that whale and human music have so much in common even though our evolutionary paths have not interested for nearly 60 million years suggests that music may predate humans. They assert that rather than being the inventors of music, we are latecomers to the musical scene. Humpback whale composers employ many of the same tricks that human songwriters do. In addition to using similar rhythms, humpbacks keep musical phrases to a few seconds, creating themes out of several phrases before singing the next one. Whale songs in general are no longer than symphony movements, perhaps because they have a similar attention span. Even though they can sing over a range of seven octaves, the whales typically sing in key, spreading adjacent notes no farther apart than a scale. They mix percussive and pure tones in pretty much the same ratios as human composers - and follow their ABA form, in which a theme is presented, elaborated on and then revisited in a slightly modified form. Perhaps most amazingly, humpback whale songs include repeating refrains that rhyme. It has been suggested that whales might use rhymes for exactly the same reasons that we do: as devices to help them remember. Whale songs can also be rather catchy. When a few humpbacks from the Indian Ocean strayed into the Pacific, some of the whales they met there quickly changed their tunes - singing the new whales'songs within three short years. Some scientists are even tempted to speculate that a universal music awaits discovery.
6: Which of the following is NOT true about humpback whale music?

Read the following passage and choose the best answer (A, B, C, D):
Another critical factor that plays a part in susceptibility to colds is age. A study done by the University of Michigan School of Public Health revealed particulars that seem to hold true for the general population. Infants are the most cold-ridden group, averaging more than six colds in their first year. Boys have more colds than girls up to age three. After the age of three, girls are more susceptible than boy's , and teenage girls average three colds a year to boy’s two. The general incidence of continues to decline into maturity. Elderly people who are in good health have as few as one or two colds annually. One exception is founds among people in the twentics, especially women, who show a rise in cold infections, because people in this age group are most likely to have young children. Adults who delay having children until thirties forties experience the same sudden increase in cold infections. The study also found that economics play an important role. As income increases, the frequency at which are reported in the family decreases. Families with the lowest income suffer about a third more colds than families at the lower end. Lower income generally forces people to live in more cramped quarters than those typically occupied by wealthier by wealthier people, and crowding increses the opportunities for the cold virus totravel from person to person. Low income may also adversely influence diet. The degree to which poor nutrition affects susceptibility to colds is not yet clearly established, but an inadequate diet is suspected of lowering resistance generally.
9: Which of the following is closest in meaning to the word "particulars" in the first paragraph?

Read the following passage and choose the best answer (A, B, C, D):
Native Americans probably arrived from Asia in successive waves over several millennia, crossing a plain hundreds of miles wide that now lies inundated by 160 feet of water released by melting glaciers. For several periods of time, the first beginning around 60,000 BC and the last ending around 7,000 BC, this land bridge was open. The first people travelled in the dusty trails of the animals they hunted. They brought with them not only their families, weapons, and tools but also a broad metaphysical understanding, sprung from dreams and visions and articulated in myth and song, which complemented their scientific and historical knowledge of the lives of animals and people. All this they shaped in a variety of languages, bringing into being oral literatures of power and beauty. Contemporary readers, forgetting the origins of western epic, lyric, and dramatic forms, are easily disposed to think of “literature” only as something written. But on reflection it becomes clear that the more critically useful as well as the more frequently employed sense of the term concerns the artfulness of the verbal creation, not its mode of presentation. Ultimately, literature is aesthetically valued, regardless of language, culture, or mode of presentation, because some significant verbal achievement results from the struggle in words between tradition and talent. Verbal art has the ability to shape out a compelling inner vision in some skillfully crafted public verbal form. Of course, the differences between the written and oral modes of expression are not without consequences for an understanding of Native American literature. The essential difference is that a speech event is an evolving communication, an “emergent form”, the shape, functions, and aesthetic values of which become more clearly realized over the course of the performance. In performing verbal art, the performer assumes responsibility for the manners as well as the content of the performance, while the audience assumes the responsibility for evaluating the performer’s competence in both areas. It is this intense mutual engagement that elicits the display of skill and shapes the emerging performance.

8. What can be inferred from the passage about the difference between written and oral literature?

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.

   Technology has utterly transformed our ability to communicate with each other. Linking to each other both literally and figuratively, many of us connect through cell phones, email, instant messaging, blogs, and networking web sites, yet we may be less connected to each other than we think.

   According to a study, Americans are becoming increasingly socially isolated. The study reveals, for example, that one quarter of Americans say that they have no one to discuss important personal issues with, and that the number of close friends that American have has dropped from three to two. Meanwhile, the Boston Globe reports that this spreading isolation is experienced more sharply among those with less education, people of color, and older Americans. Unsurprisingly, those who are young, white, and well educated tend to have stronger social networks.

   From my own experience I have to say that I’ve never felt more connected, thanks to a web of friends, family, and colleagues. One of my closest friends is someone I met through an online discussion group who lives hundreds of miles away from me. We have met face-to-face only twice, yet our regular electronic correspondence and cell phone calls sustain our close friendship. And, speaking of blogging, my blog has introduced me to people I would never have met otherwise and has led to enduring and important friendships.

   On the other hand, I recently saw a scene unfold that proved to me how deeply disconnected we as Americans have become. I had just wrapped up a presentation on mediation at a family therapy center. As I was leaving, I noticed a mother and her teenage son who had just completed their session with their family therapist. After making their next appointment, they both took out their cell phones, placed calls, and began loud conversations with whoever was on the other end. I walked out behind them to the parking lot to my car. They both jumped into their SUV, and, as I saw them drive off, they were still talking on their cell phones. But, alas, not to each other.

The word “those” in paragraph 2 refers to __________.

Read the following passage and choose the best answer (A, B, C, D):
There are many theories about the beginning of drama in ancient Greece. The one most widely accepted today is based on the assumption that drama evolved from ritual. The argument for this view goes as follows. In the beginning, human beings viewed the natural forces of the world, even the seasonal changes, as unpredictable, and they sought, through various means, to control these unknown and feared powers. Those measures which appeared to bring the desired results were then retained and repeated until they hardened into fixed rituals. Eventually stories arose which explained or veiled the mysteries of the rites. As time passed some rituals were abandoned, but the stories, later called myths, persisted and provided material for art and drama. Those who believed that drama evolved out of ritual also argue that those rites contained the seed of theater because music, dance, masks, and costumes were almost always used. Furthermore, a suitable site hard to be provided for the performances, and when the entire community did not participate, a clear division was usually made between the “acting area” and the “auditorium”. In addition, there were performers, and since considerable importance was attached to avoiding mistakes in the enactment of rites, religious leaders usually assumed that task. Wearing masks and costumes, they often impersonated other people, animals, or supernatural beings, and mimed the desired effect- success in hunt or battle, the coming rain, the revival of the Sun as an actor might. Eventually such dramatic representations were separated from religious activities. Another theory traces the theater’s origin from the human interest in storytelling. According to this view, tales (about the hunt, war or other feats) are gradually elaborated, at first through the use of impersonation, action, and dialogue by a narrator and then through the assumption of each of the roles by a different person. A closely related theory traces theater to those dances that are primarily rhythmical and gymnastic or that are imitation of animal movements and sounds.
9: According to the passage, which of the following statements is TRUE?

 Read the passage carefully, then choose the correct answer

Having a best friend to confide in can bring a positive effect on our emotional health. An evening out with the closest friend may be the best guarantee of a good time. In fact, our best friend can prevent us from developing serious psychological problems such as depression and anxiety.

Best friendship evolves with time – we cannot go out and pick our best friend. We become friends with people who share common interests – at school or through hobbies, for example.

Best friends have usually known each other for years and stuck together through good and bad times. If you haven’t got one, perhaps you are being too distant from people, or focusing too much on your work.

According to the passage, ________.

Read the following passage and choose the best answer (A, B, C, D):
Many of the most damaging and life-threatening types of weather-torrential rains, severe thunderstorms, and tornadoes-begin quickly, strike suddenly, and dissipate rapidly, devastating small regions while leaving neighboring areas untouched. One such event, a tornado, struck the northeastern section of Edmonton, Alberta, in July 1987. Total damages from the tornado exceeded $ 250 million, the highest ever for any Canadian storm. Conventional computer models of the atmosphere have limited value in predicting short-live local storms like the Edmonton tornado, because the available weather data are generally not detailed enough to allow computers to discern the subtle atmospheric changes that precede these storms. In most nations, for example, weather balloon observations are taken just once every twelve hours at locations typically separated by hundreds of miles. With such limited data, conventional forecasting models do a much better job predicting general weather conditions over large regions than they do forecasting specific local events. Until recently, the observation-intensive approach needed for accurate, very short-range forecasts, or "Nowcasts", was not feasible. The cost of equipping and operating many thousands of conventional weather stations was prohibitively high, and the difficulties involved in rapidly collecting and processing the raw weather data from such a network were insurmountable. Fortunately, scientific and technological advances have overcome most of these problems. Radar systems, automated weather instruments, and satellites are all capable of making detailed, nearly continuous observation over large regions at a relatively low cost. Communications satellites can transmit data around the world cheaply and instantaneously, and modern computers can quickly compile and analyzing this large volume of weather information. Meteorologists and computer scientists now work together to design computer programs and video equipment capable of transforming raw weather data into words, symbols, and vivid graphic displays that forecasters can interpret easily and quickly. As meteorologists have begun using these new technologies in weather forecasting offices, Nowcasting is becoming a reality.
9: With which of the following statements is the author most likely to agree?

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.

   Orchids are unique in having the most highly developed of all blossoms, in which the usual male and female reproductive organs are fused in a single structure called the column. The column is designed so that a single pollination will fertilize hundreds of thousands, and in some cases millions, of seeds, so microscopic and light they are easily carried by the breeze. Surrounding the column are three sepals and three petals, sometimes easily recognizable as such, often distorted into gorgeous, weird, but always functional shapes. The most noticeable of the petals is called the labellum, or lip. It is often dramatically marked as an unmistakable landing strip to attract the specific insect the orchid has chosen as its pollinator.

   To lure their pollinators from afar, orchids use appropriately intriguing shapes, colors, and scents. At least 50 different aromatic compounds have been analyzed in the orchid family, each blended to attract one, or at most a few, species of insects or birds. Some orchids even change their scents to interest different insects at different times.

   Once the right insect has been attracted, some orchids present all sorts of one-way obstacle courses to make sure it does not leave until pollen has been accurately placed or removed. By such ingenious adaptations to specific pollinators, orchids have avoided the hazards of rampant crossbreeding in the wild, assuring the survival of species as discrete identities. At the same time they have made themselves irresistible to collectors.

The word "discrete" in line 16 is closest in meaning to...................

Read the following passage and mark the letter A,B,C or D on your answer sheet ti indicate the correct answer to each of the questions. 
When you first apply for the job, you might not succeed in getting it. It’s always a good idea to ask them to explain to you what prevented you from beating the other candidates. Don’t complain about the situation, but ask them to advise you on what you can do better next time. Perhaps the interviewers disproved of or disagreed with something you said. Perhaps they just glance at your application and saw something that made it easy to choose between you and another candidate. Don’t regard it as a failure, but recognize it as a chance to learn more. As long as you don’t worry too much about it and continue to believe in yourself, you’ll eventually find the chance you’ve been waiting for. Then your family and friends will be congratulate you on your success !

You don’t need to worry too much ________________.

Read the following passage and choose the best answer (A, B, C, D):
When jazz began to lose its reputation as "low-down" music and to gain well-deserved acclaim among intellectuals, musicians began to feature many instruments previously considered inappropriate for jazz. Whereas before the 1950s, jazz musicians played only eight basic instruments in strict tempo, in this decade they started to improvise on the flite, electric organ, piccolo, accordion, cello, and even bagpipes, with the rhythm section composed for strings or piano. Big bands no longer dominated jazz, and most changes emerged from small combos, such as the Dave Brubeck Quartet and the Gerry Mulligan Quartet. The Gerry Mulligan Quartet proved that a small, modern band could sound complete without a piano; the rhythm section consisted only of a set of drums and a string bass. Jazz continued to move in new directions during the 1960s. Saxophonist and composer Ornette Coleman led a quartet playing "free" jazz that was atonal. Pianist Cecil Taylor also conducted similar experiments with music, and John Coltrane included melodies from India in his compositions. In the 1970s musicians blended jazz and rock music into fusion jazz which combined the melodies and the improvisations of jazz with the rhythmic qualities of rock'n' roll, with three or five beats to the bar and in other meters. The form of jazz music was greatly affected by electric instruments and electronic implements to intensify, distort, or amplify their sounds. However, the younger musicians of the time felt compelled to include a steady, swinging rhythm which they saw as a permanent and essential element in great jazz.
7. The author of the passage implies that in the 1950s, jazz musicians

Certain birds are, more often than not, considered bad luck, or even a sign of impending death. For example, all over the world, both crows and ravens have some connection to war, and death. In early times, crows and ravens were thought to accompany the gods of war, or be signs of the gods’ approaching arrival. This idea later changed. Crows in particular were thought to be harbingers of ill fortune or, in some cases, guides to the afterlife. Woe be it to the person who saw a single crow or raven flying overhead, for this was most certainly a portent of death in the near future.
 Interestingly, though potentially bad luck for people individually, the raven is considered to be good luck for the crown of England. So much so, in fact, that a “raven master” is, even today, an actual government position in London. He takes care of the ravens there and also clips their wings, ensuring that these birds can never fly far from the seat of the British government. This way, the kingdom will never fall to ill fortune.
 Another bird that is thought to play a part in forecasting the fortunes of people is the swallow. Depending on how and when it is seen, the swallow can be a harbinger of either good or ill fortune. Perhaps inspired by the swallow’s red-brown breast, Christian people initially related the swallow to the death of Jesus Christ. Thus, people who saw a swallow fly through their house considered it a portent of death. Later, however, farmers began to consider swallows signs of good fortune. Any barn that has swallows living in it is sure to be blessed in the following year. Farmers also have to beware of killing a swallow; that would be certain to end any good luck they might have had.
 Though many people think these superstitions are old wives’ tales, there is actually some evidence to support them. For example, crows and ravens, being scavengers, appear at the aftermath of battles. Thus, large numbers of crows and ravens could be good indications of war in an area. As well, swallows feed on insects that can cause infections in cattle. Thus, a farmer who has many swallows in his barn may actually have healthier animals on his farm. Therefore, the next time you feel inclined to laugh at an old wives’ tale, maybe you had better find out if there is any truth to it first!.

The word "portent" in the first paragraph is closest in meaning to ___________.

Read the text and choose the best option to fill in each blank numbered:
Keeping your distance
Personal space is a term that refers (1)_______  the distance we like to keep between ourselves and other people. When (2) _______ we do not know well gets too close we usually begin to feel uncomfortable. If a business colleague comes closer than 1.2 meters, the most common response is to move (3)______ Some interesting (4)______ have been done in libraries. If strangers come too close, many people get up and leave the building; others use different methods such as turning their back on the intruder. Living in cities has made people develop new skills for dealing with situations where they are very close to strangers. Most people on crowded trains try not to look at strangers; they avoid skin contact, and apologize if hands touch by mistake. People use newspapers (5)_______ a barrier between themselves and other people, and if they do not have one, they stare into the distance, making sure they are not looking into anyone’s eyes.

Read the passage then choose the best answer to fill in each gap.

The human …….. (16) is only one small species in the living world. Many ……. (17) species exist on this planet. However, human beings have great influence on the rest of the world. ………..(18) are changing the environment by building cities and villages where forests once stood. They are …………(19) the water supply by using water for industry and agriculture. They are changing weather conditions by cutting down trees in the forests, and they are destroying the air by adding ……….. (20) to it.

19:.......................

Read the passage and choose the best answers

In many aspects of life, effective communication skills are extremely important. With good communication skills, people can enjoy better interpersonal relationships with friends and family. The following are some guides that can help you improve your communication skills.

Learn to listen

Listening is not the same as hearing; you should learn to listen not only to the words being spoken but also how they are being spoken and the non-verbal messages sent with them. You shouldn't think about what to say next while listening; instead clear your mind and focus on the message being received. Your friends, colleagues and other acquaintances will appreciate your good listening skills.

Try to understand other people's emotions

To understand other people's emotions, you should be sympathetic to other people's misfortunes and congratulate them on their achievements. To do this, you need to be aware of what is going on in other people's lives. It's crucial to maintain eye contact and do not be afraid to ask others for their opinions as this will help to make them feel valued.

Encourage

It's advised that you offer words and actions of encouragement, as well as praise, to others, which make other people feel welcome, valued and appreciated in your communications. If you let others know that they are valued, they are much more likely to give you their best. You should also try to ensure that everyone get involved in an interaction or conversation by using effective body language and open questions.

What should listeners do while someone is speaking?

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.

   Orchids are unique in having the most highly developed of all blossoms, in which the usual male and female reproductive organs are fused in a single structure called the column. The column is designed so that a single pollination will fertilize hundreds of thousands, and in some cases millions, of seeds, so microscopic and light they are easily carried by the breeze. Surrounding the column are three sepals and three petals, sometimes easily recognizable as such, often distorted into gorgeous, weird, but always functional shapes. The most noticeable of the petals is called the labellum, or lip. It is often dramatically marked as an unmistakable landing strip to attract the specific insect the orchid has chosen as its pollinator.

   To lure their pollinators from afar, orchids use appropriately intriguing shapes, colors, and scents. At least 50 different aromatic compounds have been analyzed in the orchid family, each blended to attract one, or at most a few, species of insects or birds. Some orchids even change their scents to interest different insects at different times.

   Once the right insect has been attracted, some orchids present all sorts of one-way obstacle courses to make sure it does not leave until pollen has been accurately placed or removed. By such ingenious adaptations to specific pollinators, orchids have avoided the hazards of rampant crossbreeding in the wild, assuring the survival of species as discrete identities. At the same time they have made themselves irresistible to collectors.

The word "their" in line 12 refers to.................

Read the following passage and choose the best answer (A, B, C, D):
Many of the most damaging and life-threatening types of weather-torrential rains, severe thunderstorms, and tornadoes-begin quickly, strike suddenly, and dissipate rapidly, devastating small regions while leaving neighboring areas untouched. One such event, a tornado, struck the northeastern section of Edmonton, Alberta, in July 1987. Total damages from the tornado exceeded $ 250 million, the highest ever for any Canadian storm. Conventional computer models of the atmosphere have limited value in predicting short-live local storms like the Edmonton tornado, because the available weather data are generally not detailed enough to allow computers to discern the subtle atmospheric changes that precede these storms. In most nations, for example, weather balloon observations are taken just once every twelve hours at locations typically separated by hundreds of miles. With such limited data, conventional forecasting models do a much better job predicting general weather conditions over large regions than they do forecasting specific local events. Until recently, the observation-intensive approach needed for accurate, very short-range forecasts, or "Nowcasts", was not feasible. The cost of equipping and operating many thousands of conventional weather stations was prohibitively high, and the difficulties involved in rapidly collecting and processing the raw weather data from such a network were insurmountable. Fortunately, scientific and technological advances have overcome most of these problems. Radar systems, automated weather instruments, and satellites are all capable of making detailed, nearly continuous observation over large regions at a relatively low cost. Communications satellites can transmit data around the world cheaply and instantaneously, and modern computers can quickly compile and analyzing this large volume of weather information. Meteorologists and computer scientists now work together to design computer programs and video equipment capable of transforming raw weather data into words, symbols, and vivid graphic displays that forecasters can interpret easily and quickly. As meteorologists have begun using these new technologies in weather forecasting offices, Nowcasting is becoming a reality.
1. What does the passage mainly discuss?

By the mid-nineteenth century, the term "icebox" had entered the American language, but ice was still only beginning to affect the diet of ordinary citizens in the United States. The ice trade grew with the growth of cities. Ice was used in hotels, taverns, and hospitals, and by some forward-looking city dealers in fresh meat, fresh fish, and butter. After the Civil War (1860-1865), as ice was used to refrigerate freight cars, it also came into household use. Even before 1880, half the ice sold in New York, Philadelphia, and Baltimore, and one-third of that sold in Boston and Chicago, went to families for their own use. This had become possible because a new household convenience, the icebox, a precursor of the modern refrigerator, had been invented.
 Making an efficient icebox was not as easy as we might now suppose. In the early nineteenth century, the knowledge of the physics of heat, which was essential to a science of refrigeration, was rudimentary. The common-sense notion that the best icebox was one that prevented the ice from melting was of course mistaken, for it was the melting of the ice that performed the cooling. Nevertheless, early efforts to economize ice included wrapping the ice in blankets, which kept the ice from doing its job. Not until near the end of the nineteenth century did inventors achieve the nice balance of insulation and circulation needed for an efficient icebox.
 But as early as 1803, an ingenious Maryland farmer, Thomas Moore, had been on the right track. He owned a farm about twenty miles outside the city of Washington, for which the village of Georgetown was the market center. When he used an icebox of his own design to transport his butter to market, he found that customers would pass up the rapidly melting stuff in the tubs of his competitors to pay a premium price for his butter, still fresh and hard in neat, one-pound bricks. One advantage of his icebox, Moore explained, was that farmers would no longer have to travel to market at night in order to keep their produce cool.

According to the passage, which of the following was an obstacle to the development of the icebox?