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).........................

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 the United States, friendship can be close, constant, intense, generous and real, yet fade away in a short time if circumstances change. Neither side feels hurt by this. Both may exchange Christmas greetings for a year or two, perhaps a few letters for a while - then no more. If the same two people meet again by chance, even years later, they pick up the friendship where they left off and are delighted.
In the United States, you can feel free to visit people's homes, share their holidays, or enjoy their lives without fear that they are taking on a lasting obligation. Do not hesitate to accept hospitality because you can’t give it in turn. No one will expect you to do so for they know you are far from home. Americans will enjoy welcoming you and be pleased if you accept their hospitality easily.
Once you arrived there, the welcome will be fun, warm, and real. Most visitors find themselves readily invited into many homes there. In some countries it is considered inhospitable to entertain at home, offering what is felt as only home cooked food, not doing something for your guests." It is felt that restaurant entertaining shows more respect and welcome. Or for other different reasons, such as crowded space, language difficulties, or family customs, outsiders are not invited into homes.
In the United States, both methods are used, but it is often considered friendlier to invite a person to one's home than to go to a public place, except in purely business relationship. So, if your host or hostess brings you home, do not feel that you are being shown inferior treatment.
Don't feel neglected if you do not find flowers awaiting you in your hotel room, either. Flowers are very expensive there; hotel delivery is uncertain; arrival times are delayed, changed or cancelled - so flowers are not customarily sent as a welcoming touch. Please do not feel unwanted! Outward signs vary in different lands; the inward welcome is what matters, and this will be real.

Which of the following is the best title for this passage?

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Loneliness is a curious thing. Most of us can remember feeling most lonely when we were not in fact alone at all, but when we were surrounded by people. Everyone has experienced, at some time, that utter sense of isolation that comes over you when you are at a party, in a room full of happy laughing people, or in an audience at a theatre or a lecture. It suddenly seems to you as if everybody knows everybody else, everybody is sure of himself, everybody knows what is going on; everybody, that is, except you. This feeling of loneliness which can overcome you when are in a crowd is very difficult to get rid of. People living alone - divorced, widowed or single people - are advised to tackle their loneliness by joining a club or society, by going out and meeting people. Does this really help? And what do you do if you are already surrounded by people? There are no easy solutions. Your first day at work, or at a new school or university, is a typical situation in which you are likely to feel lonely. You feel lonely because you feel left out of things. You feel that everybody else is full of confidence and knows what to do, but you are adrift and helpless. The fact of the matter is that, in order to survive, we all put on a show of self-confidence to hide our uncertainties and doubts. So it is wrong to assume that you are alone. In a big city it is particularly easy to get the feeling that everybody except you is leading a full, rich, busy life. Everybody is going somewhere, and you tend to assume that they are going somewhere nice and interesting, where they can find life and fulfilment. You are also going somewhere, and there is no reason at all to believe that your destination is any less, or, for that matter, any more exciting than the next man's. The trouble is that you may not be able to hide the fact that you are lonely, and the miserable look on your face might well put people off. After all, if you are at a party you are not likely to try to strike up a conversation with a person who has a gloomy expression on his face and his lips turned down at the comers. So trying to look reasonably cheerful is a good starting point in combating loneliness, even if you are choking inside. The next thing to avoid is finding yourself in a group where in fact you are a stranger, that is, in the sort of group where all the other people already know each other. There is a natural tendency for people to stick together, to form 'cliques'. You will do yourself no good by trying to establish yourself in a group which has so far managed to do very well without you. Groups generally resent intrusion, not because they dislike you personally, but because they have already had to work quite hard to turn the group into the functioning unit. To include you means having to go over a lot of ground again, so that you can learn their language, as it was, and get involved in their conversation at their level. Of course if you can offer something the group needs, such as expert information, you can get in quickly. In fact the surest way of getting to know others is to have an interest in common with them. There is no guarantee that you will then like each other, but at least part of your life will be taken up with sharing experiences with others. It is much better than always feeling alone. If all this seems to be a rather pessimistic view of life, you have to accept the fact that we are all alone when it comes down to it. When the most loving couple in the world kiss and say goodnight, as soon as the husband falls asleep, the wife realizes that she is alone, that her partner is as far away as if he were on another planet. But it is no cause for despair: there is always tomorrow.

In a city it is easy to believe that other people,,,,,,,,,,,,,,,,,,,,,,,,,

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Footracing is a popular activity in the United States. It is seen not only as a competitive sport but also as a way to exercise, to enjoy the camaraderie of like–minded people, and to donate money to a good cause. Though serious runners may spend months training to compete, other runners and walkers might not train at all. Those not competing to win might run in an effort to beat their own time or simply to enjoy the fun an exercise. People of all ages. From those of less than one year (who may be pushed in strollers) to those in their eighties, enter into this sport. The races are held on city streets, on college campuses, through parks, and in suburban areas, and they are commonly 5 to 10 kilometers in length.
The largest footrace in the world is the 12 kilometer Bay to Breakers race that is held in San Francisco every spring. This race begins on the east side of the city near San Francisco Bay and ends on the west side at the Pacific Ocean. There may be 80,000 or more people running in this race through the streets and hills of San Francisco. In the front of are the serious runners who compete to win and who might finish in a little as 34 minutes. Behind them are the thousands who take several hours to finish. In the back of the race are those who dress in costumes and come just for fun. One year there was a group of men who dresses like Elvis Presley, and another group consisted of the firefighters who were tired together in a long line and who were carrying a firehose. There was even a bridal party, in which the bride was dressed in a long white gown and the groom wore a tuxedo. The bride and groom threw flowers to bystanders, and they were actually married at some point along the route.

Which of the following best describes the organization of this passage?

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Halloween falls on October 31 each year in North America and other part of the world. What do you know about Halloween? Do you celebrate it in your country? Here is a little history about it?
Like other holidays, Halloween has evolved and changed throughout history. Over 2,000 years ago people called the Celts lived in what is now Ireland, the UK, and parts of Northern France. November 1 was their New Year's Day. They believed that the night before the New Year (October 31) was a time when the living and the dead came together.
More than a thousand years ago the Christian church named November 1 All Saints Day (also called All Hallows). This was a special holy day to honor the saints and other people who died for their religion. The night before All Hallows was called Hallows Eve. Later the name was changed to Halloween.
Like the Celts, the Europeans of that time also believed that the spirits of the dead would visit the earth on Halloween. They worried that evil spirits would cause problems or hurt them. So on that night people wore costumes that looked like ghosts or other evil creatures. They thought if they dressed like that, the spirits would think they were also dead and not harm them.
The tradition of Halloween was carried to America by the immigrating Europeans. Some of the traditions changed a little, though. For example, on Halloween in Europe some people would carry lanterns made from turnips. In America, pumpkins were more common. So people began putting candles inside them and using them as lanterns. That is why you see Jack 'o lanterns today.
These days Halloween is not usually considered a religious holiday. It primarily a fun for children. Children dress up in costumes like people did a thousand years ago. But instead of worrying about evil spirits, they go from house to house. They knock on door and say "trick or treat". The owner of each house give candy or something special to each trick and treat.

According to the passage, which of the following can result from the carrying Halloween to America?

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:
Genetic modification of foods is not a new practice. It has been practiced for thousands of years under the name of "selective breeding". Animals and plants were chosen because they had traits that humans found useful. Some animals were larger and stronger than others, or they yielded more food, or they had some other trait that humans valued. Therefore, they were bred because of those traits. Individuals with those traits were brought together and allowed to breed in the hope that their offspring would have the same traits in greater measure.
Much the same thing was done with plants. To produce bigger or sweeter fruit, or grow more grain per unit of land, strains of plants were combined and recombined to produce hybrids, or crossbreeds that had the desired traits in the right combinations. All the while, however, biologists wondered: is there a more direct and versatile way to change the traits of plants and animals? Could we rewrite, so to speak, the heredity of organisms to make them serve our needs better?
In the 20th century, genetic modification made such changes possible at last. Now, it was possible to alter the genetic code without using the slow and uncertain process of selective breeding. It even became possible to blend plants and animals genetically: to insert animal genes into plants, for example, in order to give the plants a certain trait they ordinarily would lack, such as resistance to freezing. The result was a tremendous potential to change the very nature of biology.

The word "them" in paragraph 2 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.
(4).........................

There are many theories about the beginning of drama in ancient Greek. 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 theatre because music, dance, masks, and costumes were almost always used. Furthermore, a suitable site had to be provided for performances, and when the entire community did not participate, a clear division was usually made between the “acting area” and “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 theatre’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 theatre to those dances that are primarily rhythmical and gymnastic or that are imitations of animal movements and sound.

The passage supports which of the following statements?

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:
Halloween falls on October 31 each year in North America and other part of the world. What do you know about Halloween? Do you celebrate it in your country? Here is a little history about it?
Like other holidays, Halloween has evolved and changed throughout history. Over 2,000 years ago people called the Celts lived in what is now Ireland, the UK, and parts of Northern France. November 1 was their New Year's Day. They believed that the night before the New Year (October 31) was a time when the living and the dead came together.
More than a thousand years ago the Christian church named November 1 All Saints Day (also called All Hallows). This was a special holy day to honor the saints and other people who died for their religion. The night before All Hallows was called Hallows Eve. Later the name was changed to Halloween.
Like the Celts, the Europeans of that time also believed that the spirits of the dead would visit the earth on Halloween. They worried that evil spirits would cause problems or hurt them. So on that night people wore costumes that looked like ghosts or other evil creatures. They thought if they dressed like that, the spirits would think they were also dead and not harm them.
The tradition of Halloween was carried to America by the immigrating Europeans. Some of the traditions changed a little, though. For example, on Halloween in Europe some people would carry lanterns made from turnips. In America, pumpkins were more common. So people began putting candles inside them and using them as lanterns. That is why you see Jack 'o lanterns today.
These days Halloween is not usually considered a religious holiday. It primarily a fun for children. Children dress up in costumes like people did a thousand years ago. But instead of worrying about evil spirits, they go from house to house. They knock on door and say "trick or treat". The owner of each house give candy or something special to each trick and treat.

The passage is mainly about?

Choose the best answer: 
By the time we (1)________old age most of us have (2)________twenty years sleeping. Yet nobody knows why we do it. Most scientists believe that by resting our bodies, we allow time for(3) ________ maintenance work to be done. Any (4)________that there is can be put right more quickly if energy isn’t being used up doing other things. Sleep is controlled by certain chemicals. These build up during the day, eventually reaching peaks that cause tiredness. We can control the effects of these chemicals to some extent. Caffeine helps to (5)________ us awake while alcohol and some medicines make us sleepy. By using electrodes, scientists are able to (6)________what goes on in people’s heads while they sleep. They have (7)________that when we first drop off everything slows down. The heart (8)________ more slowly and our breathing becomes shallow.
After about 90 minutes our eyes start to twitch and we go into what is called REM (Rapid Eye Movement) sleep, which is a (9)________that we’ve started to dream .You have dreams every night, even if you don’t remember them. There are many theories
about why we dream, none of them conclusive. A lot of people say they have to have eight hours’ sleep every night while others seem to (10)________on a lot less. One thing’s for sure – we all need some sleep. Going without it can have some very strange effects.
 

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.
Nearly 200 of the 1500 native plant species in Hawaii are at risk of going extinct in the near future because they have been (1)........  to such low numbers. Approximately 90 percent of Hawaii's plants are   found nowhere else in the world but they are (2)........ by alien invasive species such as feral goats, pigs, rodents and non-native plants.
The Hawaii Rare Plant Restoration Group is striving to (3)........ the extinction of the 182 rare  Hawaiian plants with fewer than 50 individuals remaining in the wild. Since 1990, (4).......  a result of     their "Plant Extinction Prevention Program", sixteen species have been brought into cultivation and three species have been reintroduced. Invasive weeds have been removed in key areas and fencing put up in order to protect plants in the wild.
In the future, the Hawaii Rare Plant Restoration Program aims at collecting genetic material from the remaining plants in the wild for storage as a safety net for the future. They also aim to manage wild populations and where possible reintroduce species into (5 )........ .
(2)................................

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 geologists call the Basin and Range Province in the United States roughly coincides in its northern portions with the geographic province known as the Great Basin. The Great Basin is hemmed in west by the Sierra Nevada and on the east Line by the Rocky Mountains; it has no outlet to the sea. The prevailing winds in the Great Basin are from the west. Warm, moist air from the Pacific Ocean is forced upward as it crosses the Sierra Nevada. At the higher altitudes it cools and the moisture it carries is precipitated as rain or snow on the western slopes of the mountains. That which reaches the Basin is air wrung dry of moisture. What little water falls there as rain or snow, mostly in the winter months, evaporates on the broad, flat desert floors. It is, therefore, an environment in which organisms battle for survival. Along the rare watercourses, cottonwoods and willows eke out a sparse existence. In the upland ranges, pinion pines and junipers struggle to hold their own.
But the Great Basin has not always been so arid. Many of its dry, closed depressions were once filled with water. Owens Valley, Panamint Valley, and Death Valley were once a string of interconnected lakes .The two largest of the ancient lakes of the Great Basin were Lake Lahontan and Lake Bonneville. The Great Salt Lake is all that remains of the latter, and Pyramid Lake is one of the last briny remnants of the former. There seem to have been several periods within the last tens of thousands of years when water accumulated in these basins. The rise and fall of the lakes were undoubtedly linked to the advances and retreats of the great ice sheets that covered much of the northern part of the North American continent during those times.
Climatic changes during the Ice Ages sometimes brought cooler, wetter weather to mid latitude deserts worldwide, including those of the Great Basin. The broken valleys of the Great Basin provided ready receptacles for this moisture.

According to the passage, what does the Great Basin lack?

Read the following passage and choose among A, B, C or D the correct answer to each of the questions.

There has been much debate over the past few decades concerning fears that nation will

lead to robots replacing human workers on a massive scale.

The increasing use of robotics, computers and artificial intelligence is a reality, but its full

implications are far from cut and dried. Some forecasts present the future in a utopian way,

claiming that robots will take over the tedious heavy work thus freeing up human time and

potential, allowing for more creativity and innovation,  the other end of spectrum are those who

foresee an employment apocalypse, predicting that almost fifty percent of all American jobs

could vanish within the next few decades. Former Microsoft chairman Bill Gates states that in 20

years robots could be in place in a number of job categories, particularly those at lower end of

the scale in terms of skills. The bottom line is that while the future is always uncertain, robots are a fixture of our society, which is not going to disappear. As with the Industrial Revolution, where machines were utilized in many tasks in place of manual laborers and social upheaval followed, the Digital Revolution is likely to place robots in various jobs. In spite of that, many of today's jobs were not in existence before the Industrial Revolution, such as those of programmers, engineers and data scientists. This leads other experts to criticize this alarmist approach of robot scare-mongering, which is invariably compared to the 19th -century "Luddites". This group was textile workers who feared being displaced by machines and resorted to violence, burning down factories and destroying industrial equipment - their rejection of inevitable progress has come to symbolize mindless ignorance.

Needless to say, exactly what new kinds of jobs might exist in the future is difficult to envision at present. Therefore, the crux of the issue is not whether jobs will be lost, but whether the creation of new vacancies will outpace the ever-increasing number of losses and what skills will be required in the future.

It is clearly not all doom and gloom, as demand for employees with skills in data analysis, coding, computer science, artificial intelligence and human-machine interface is rising and will continue to do so. Furthermore, the demand for skills in Jobs where humans surpass computers, such as those involving care, creativity and innovative craftmanship, are likely to increase considerably. Ultimately, the key lies in the adaptation of the workforces, through appropriate education and training, to keep pace with our world's technological progress.

According to the article, which quality will technology never be able to replace?

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
Choosing clothes can be difficult. Some people want to be fashionable, but they don’t want to look exactly like everybody else. Not all clothes are (1)........ for work or school, perhaps because they are not formal enough, or simply not comfortable. It is easy to buy the (2).......... size, and find that your trousers are too tight, especially if you are a little bit overweight. Very (3)........clothes make you feel slim, but when they have shrunk in the washing machine, then you have the same problem! If you buy light cotton clothes, then they might not be (4)........ enough for winter. If your shoes are not waterproof and if you aren’t (5)....... for the cold, you might look good, but feel terrible!
(3).................................

There are many theories about the beginning of drama in ancient Greek. 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 theatre because music, dance, masks, and costumes were almost always used. Furthermore, a suitable site had to be provided for performances, and when the entire community did not participate, a clear division was usually made between the “acting area” and “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 theatre’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 theatre to those dances that are primarily rhythmical and gymnastic or that are imitations of animal movements and sound.

Which of the following is NOT mentioned as a common element of theatre and ritual?

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.

Which of the following is closest in meaning to the word “admits” in line 4?

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.
(3)................................

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Every year about two million people visit Mount Rushmore, were the faces of four U.S presidents were carved in granite by sculptor Gutzon Borglum and his son, the late Lincoln Borglum. The creation of the Mount Rushmore monument Line took 14 years – from 1927 to 1941 – and nearly a million dollars. There were times when money was difficult to come by and many people were jobless. To move more than 400,000 tons of rock, Borglum hired laid-off workers from the closed-down mines in the Black Hills area. He taught these men to dynamite, drill, carve, and finish the granite as they were hanging in midair in his specially devised chairs, which had many safety features. Borglum was proud of the fact that no workers were killed or severely injured during the years of blasting and carving.
During the carving, many changes in original design had to be made to keep the carved heads free of large fissures that were uncovered. However, not all the cracks could be avoided, so Borglum concocted a mixture of granite dust, white lead, and linseed oil to fill them.
Every winter, water from melting snows gets into the fissures and expands as it freezes, making the fissures bigger. Consequently, every autumn maintenance work is done to refill the cracks. The repairers swing out in space over a 500-foot drop and fix the monument with the same mixture that Borglum used to preserve this national monument for future generations.

This passage is mainly about      

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    .