Read the passage carefully and choose the correct answer.

The excitement of snorkelling in a clear tropical sea is hard to explain to someone who hasn't done it. If you expect to have the opportunity of trying it when on holiday, it is well worth bringing a snorkel if you can get hold of one. Experts now recommend a separate breathing tube.

Many swimmers take a deep breath before diving with a snorkel. This is a mistake, because it makes the body so light that you dive with difficulty. It is best to take a couple of deep breaths and then a normal relaxed breath in order to breathe in enough for dive. Don't take repeated deep breaths before diving because this can lead to shortage of oxygen, which causes unconsciousness without warning.

The backs of many snorkellers get badly burnt, for the snorkellers are so involved in the world below they forget about the dangers of sunburn. The sea does not protect your back from the rays of the sun, and it is best to wear a T-shirt. Snorkellers should also consider wearing shoes (or slippers), which may protect their feet from cuts from sharp rocks which can easily become infected.

Snorkellers should wear shoes while diving________.

The habits of those who constantly play video games are very important to people  working in video- game industry. If video games are going to be one of the most attractive  features of future interactive systems, it is essential for producers to know what types of games  to make, how best to present such games on interactive video and how to ensure that such  games maintain their fascination for people. Above all, it is vital to build up detailed profiles  of people who are addicted to video 
games. 
Until recently, the chief market for video games has been boys aged eight to fifteen. The  fascination for interactive video games is seen in its purest form in this group. Video games  appeal to some deep instinct in boys who find it impossible to tear themselves away from them.  Schoolwork is ignored, health is damaged and even eating habits are affected. Girls of the same  age, however, are entirely different, demonstrating far greater freedom from the hold of video  games. Quite simply, they can take video games in their stride, being able to play them when they  want and then leave them alone. 

............................ have different attitude towards playing video games. 

Read the passage below and choose one correct answer for each question.

There is very little documentation about the origins of water polo. It is known, however, that the sport originated in the rivers and lakes of mid-19th century England as an aquatic version of rugby. Early games used an inflated rubber ball that came from India known as a "pulu" (the single Indian word for all "balls"). Pronounced "polo" by the English, both the game and the ball became known as "water polo". To attract more spectators to swimming exhibitions, the London Swimming Association designed a set of water polo rules for indoor swimming pools in 1870. At first, players scored by planting the ball on the end of the pool with both hands. A favorite trick of the players was to place the five-to-nine inch rubber ball inside their swimming suit and dive under the murky water, they would then appear again as close to the goal as possible. The introduction of the rules by Scottish players changed the nature of water polo. It became a game that emphasized swimming, speed and passing. Scottish rules moved from a rugby variant to a soccer style of play. Goals became a cage of 10x 3 feet and a goal could be scored by being thrown. Players could only be tackled when they "held" the ball and the ball could no longer be taken under water. The small rubber ball was replaced by a leather soccer ball. If the player came up too near the goal, he was promptly jumped on by the goalie, who was permitted to stand on the pool deck. Games were often nothing more than gang fights in the water as players ignored the ball, preferring underwater wrestling matches that usually ended with one man floating to the surface unconscious. Water polo was first played in the USA in 1888. The game featured the old rugby style of play which resembled American football in the water. "American style" water polo became very popular and by the late 1890s was played in such venues as Madison Square Garden and Boston's Mechanics Hall, attracting 14,000 spectators to national championship games.

The present water polo ball is made of _______.

For more than six million American children, coming home after school means coming  back to an empty house. Some deal with the situation by watching TV. Some may hide. But all of  them have something in common. They spend part of each day alone. They are called “latchkey children”. They are children who look after themselves while their parents work. And their bad  condition has become a subject of concern. 
Lynette Long was once the principal of an elementary school. She said, “We had a school rule against wearing jewelry. A lot of kids had chains around their necks with keys attached. I was  constantly telling them to put the keys inside shirts. There were so many keys; it never came to  my mind what they meant.” Slowly, she learned that they were house keys. She and her husband began talking to the children who had keys. They learned of the effect working couples and single parents were having on their children. Fear was the biggest problem faced by children at home alone. One in three latchkey children the Longs talked to reported being  frightened. Many had nightmares and were worried about their own safety. The most common way latchkey children deal with their fears is by hiding. They may hide  in a shower stall, under a bed or in a closet. The second is TV. They often turn the volume up. It’s  hard to get statistics on latchkey children, the Longs have learned. Most parents are slow to admit  that they leave their children alone.

What do latchkey children suffer most from when they are at home alone?

Read the passage below and choose one correct answer for each question.

There is very little documentation about the origins of water polo. It is known, however, that the sport originated in the rivers and lakes of mid-19th century England as an aquatic version of rugby. Early games used an inflated rubber ball that came from India known as a "pulu" (the single Indian word for all "balls"). Pronounced "polo" by the English, both the game and the ball became known as "water polo". To attract more spectators to swimming exhibitions, the London Swimming Association designed a set of water polo rules for indoor swimming pools in 1870. At first, players scored by planting the ball on the end of the pool with both hands. A favorite trick of the players was to place the five-to-nine inch rubber ball inside their swimming suit and dive under the murky water, they would then appear again as close to the goal as possible. The introduction of the rules by Scottish players changed the nature of water polo. It became a game that emphasized swimming, speed and passing. Scottish rules moved from a rugby variant to a soccer style of play. Goals became a cage of 10x 3 feet and a goal could be scored by being thrown. Players could only be tackled when they "held" the ball and the ball could no longer be taken under water. The small rubber ball was replaced by a leather soccer ball. If the player came up too near the goal, he was promptly jumped on by the goalie, who was permitted to stand on the pool deck. Games were often nothing more than gang fights in the water as players ignored the ball, preferring underwater wrestling matches that usually ended with one man floating to the surface unconscious. Water polo was first played in the USA in 1888. The game featured the old rugby style of play which resembled American football in the water. "American style" water polo became very popular and by the late 1890s was played in such venues as Madison Square Garden and Boston's Mechanics Hall, attracting 14,000 spectators to national championship games.

In water polo, the players score a goal by _______.

Read the text below and decide which answer (A,B,C, or D) best fits each space.
In a world where 2 billion people live in homes that don't have light bulbs, technology holds  the key (1)_______ banishing poverty. Even the simplest technologies can transform lives and  save money. Vaccines, crops, computers and sources of solar energy can all reduce poverty in  developing countries. For example, cheap oral-rehydration therapy developed in Bangladesh  has dramatically cut the death (2) _______ from childhood diarrhoea. 
But even when such technologies exist, the depressing fact is that we can’t make them (3)  _______ for those who most need them. Solar panels, batteries and light bulbs are still beyond  the purse of many, but where they have been installed they change lives. A decent light in the evening gives children more time for homework and extends the productive day for adults.  Kenya has a thriving solar industry and six years ago Kenyan pioneers also (4) _______  connecting schools to the Internet via radio links. These people were fortunate (5) _______  being able to afford solar panels, radios and old computers. How much bigger would the  impact be if these things (6) _______ and priced specifically for poor people? Multinationals must become part of the solution, because (7)_______ they own around 60 per  cent of the world's technology, they seldom make products for poor customers. Of 1,223 new  drugs marketed worldwide from 1975 to 1996, for example, just 13 were for tropical diseases. People think those enterprises should do more to provide vital products such as medicines (8) _______ different prices around the world to suit (9) _______ people can afford.  Alternatively, they could pay a percentage of their profit towards research and development  for (10) _______. 

Question 4: .....................

Read the passage carefully and choose the correct answers:
Synchronized swimming is a hybrid of swimming, gymnastics, and dance. This sport has an artistic effect, and really relates to those three sports. It consists of swimmers performing a synchronized routine of elaborate and dramatic moves in the water, accompanied by music.
Synchronized swimming demands first-rate water skills, and requires strength, endurance, flexibility, grace, artistry and precise timing, not to mention exceptional breath control while upside down underwater. Developed in the early 1900s in Canada, it is a sport performed almost exclusively by women, although there is some participation by men. In its early form it was sometimes known as “water ballet”.
It is a Summer Olympic Games sport. First demonstrated in 1952, it has been an official event since 1984. Olympic and world Championship competition is not currently open to men, but other international and national competitions allow male competitors. Both USA Synchro and Synchro Canada allow men to compete with women.
Competitors point to the strength, flexibility, and aerobic endurance required to perform difficult routines for the judges, one technical and one free.

The best title for the passage is _______ .

Read the text below and decide which answer (A,B,C, or D) best fits each space.
Health and fitness are not just for young people. They are for anyone willing to accept the (1) _______ for a good diet and (2) _______ exercise. With age, there is a tendency to feel that  the body is no longer able to (3) _______. Aches and pains are (4) _______ normal. Instead of  pushing the body to do (5) _______, activities become limited. Yet examples after examples  have shown us that older people can – and should – be (6) 
_______. Men and women in their sixties have run in marathons, races of more than twenty six miles. Some professional athletes stay (7) _______ into their forties and fifties. For most  people, simple activities like walking and swimming are all that is needed to stay in (8)  _______. It’s important to include exercise in your daily routine. In the winter, (9) _______  push-ups, sit-ups, and other indoor exercises. Of course, such exercises will be of little use  (10) _______ you follow them with soda and chips. 

Câu 6......................

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 peregrine falcon, a predatory bird indigenous to North America, was once in danger of extinction. In the 1960s, scientists discovered byproducts of the pesticide DDT in the birds' eggs, which caused them to be too soft to survive. The use of the pesticide had been banned in the United States, but the falcons were eating migratory birds from other places where DDT was still used. In order to increase the survival rate, scientists were raising the birds in laboratories and then releasing them into mountainous areas. This practice achieved only moderate success, however, because many of the birds raised in captivity could not survive in the wild.

There is now, however, a new alternative to releases in the wild. A falcon that has been given the name Scarlett chose to make her home on a ledge of the 33rd floor of a Baltimore, Maryland, office building rather than in the wild, and, to the surprise of the scientists, she has managed to live quite well in the city. Following this example, programs have been initiated that release birds like Scarlett into cities rather than into their natural wild habitat. These urban releases are becoming a common way to strengthen the species. Urban homes have several benefits for the birds that wild spots do not. First, there is an abundance of pigeons and small birds as food sources. The peregrine in the city is also protected from its main predator, the great horned owl. Urban release programs have been very successful in reestablishing the peregrine falcons along the East Coast. Though they are still an endangered species, their numbers increased from about 60 nesting pairs in 1975 to about 700 pairs in 1992. In another decade the species may flourish again, this time without human help.

According to the passage, which of the falcon’s main predators?

Read the text below and decide which answer (A,B,C, or D) best fits each space.
THE HISTORY OF FOOTBALL

Football, or soccer, which is so popular all over the world, dates back to the Middle Ages.  At  that  (58)  ……..  it  was  very  different   from  the  game  we  play  today.  Any number of players could (59) …….. part and the matches usually developed into a free- for-all. In its modern (60) …….. , football is less than two hundred years old.

In 1846, the  first  rules  to  govern  the  game were  drawn (61) …….. at  Cambridge University. The number of players was (62) …….. to 11 per side, which made things much more (63) …….. than before. Later, in 1863, the Football Association was (64)…….. up to help promote the game in Britain.

The game is played on a grass or artificial (65) …….. with a goal net at each end. The (66) …….. is to move the ball around the field, (67) …….. the feet or head, until a player is in a (68) …….. to put the ball into the net and score a goal.

Professional football is not only the most popular (69) …….. sport in the world, (70)…….. also more people actually play football themselves than any other team sport. In 1904 FIFA, the world governing (71) …….. of football, was founded. It organizes the World Cup tournament every four years. Other kinds of football are popular, but less (72) …….. , for example American Football and Australian Rules Football.

61.......................

Fill in each numbered blank with one suitable word or phrase

Rowing is a sport in which athletes race against each other on river, lakes or on the ocean, (1) _____ on the type of race and the discipline. The boats are propelled by the reaction forces on the oar blades (2) _____ they are pushed against the water. The sport can be both recreational, focusing (3)____ learning the techniques required, and competitive where overall fitness plays a large role. It is also one of (4) _____ oldest Olympic sports. In the United States, Australia and Canada, high school and collegial rowing is sometimes referred to as crew.

(5) _____ rowing, the athlete sits in the boat facing backwards, towards the stern, and uses the oars which are held in (6) ____ by the oarlocks to propel the boat forward, towards the bow. It is a demanding sport requiring strong core balance as well as physical (7) _____ and cardiovascular endurance.

Since the action of rowing (8) _____ fairly popular throughout the world, there are many different types of (9) _____. These include endurance races, time trials, stake racing, bumps racing, and the side-by-side format used in the Olympic Games. The many different formats are a result of the long (10) _____ of the sport, its development in different regions of the world, and specific local requirements and restrictions.

(9) ________

Read the following passage and choose the best answer for each blank.

As well as being a necessary life-saving skill, swimming also (26)________us with a source of great pleasure and relaxation. Swimming, as well as other water sports like diving, surfing or just floating on your back, are some of the best ways to have (27)________and keep fit at the same time. Water sports are enjoyable for people of (28)________ages and even babies can learn to swim.

For elderly people or (29)________with physical handicaps, swimming provides gentle, yet effective exercise. Swimming for fitness and recreation has been popular (30) ________the earliest times, for instance in ancient Egypt, Greece and Roma. Swimming competitions developed in the nineteenth century and swimming races were (31)_______ in the first of the modern Olympic Games in 1896. Now water sports are (32)________ all over the world and most towns have at least one swimming pool.

Most water sports - swimming, surfing and water-skiing, etc, take (33)________on the surface of the water, but scuba divers explore deep below the waves.

There they can find fascinating sea creatures and strange rockformations. Some archaeologists are divers. (34)________search the seabed for wrecks of ships sunk hundreds of years ago which (35)________ objects that show how people lived in ancient times.

(35)________

Read the passage below and choose one correct answer for each question.

There is very little documentation about the origins of water polo. It is known, however, that the sport originated in the rivers and lakes of mid-19th century England as an aquatic version of rugby. Early games used an inflated rubber ball that came from India known as a "pulu" (the single Indian word for all "balls"). Pronounced "polo" by the English, both the game and the ball became known as "water polo". To attract more spectators to swimming exhibitions, the London Swimming Association designed a set of water polo rules for indoor swimming pools in 1870. At first, players scored by planting the ball on the end of the pool with both hands. A favorite trick of the players was to place the five-to-nine inch rubber ball inside their swimming suit and dive under the murky water, they would then appear again as close to the goal as possible. The introduction of the rules by Scottish players changed the nature of water polo. It became a game that emphasized swimming, speed and passing. Scottish rules moved from a rugby variant to a soccer style of play. Goals became a cage of 10x 3 feet and a goal could be scored by being thrown. Players could only be tackled when they "held" the ball and the ball could no longer be taken under water. The small rubber ball was replaced by a leather soccer ball. If the player came up too near the goal, he was promptly jumped on by the goalie, who was permitted to stand on the pool deck. Games were often nothing more than gang fights in the water as players ignored the ball, preferring underwater wrestling matches that usually ended with one man floating to the surface unconscious. Water polo was first played in the USA in 1888. The game featured the old rugby style of play which resembled American football in the water. "American style" water polo became very popular and by the late 1890s was played in such venues as Madison Square Garden and Boston's Mechanics Hall, attracting 14,000 spectators to national championship games.

The present rules of water polo were invented _______.

 Choose the word or phrase among A, B, C or D that best fits the blank space in the following passage:

"Many outdoor (1)….. enjoy canoeing or kayaking (2) ….. recreation on ponds, lakes, and rivers. Some people use canoes and kayaks to travel across bodies of water to remote camping locations. They (3)…. Their supplies, such as tents, sleeping bags, and food, in their boats. The Boundary Waters Canoe Area Wilderness and Voyageurs National Park, both (4)…..  along the border between Minnesota and Ontario, Canada, are two of the most popular canoeing areas in North America.
 Whitewater canoeing and kayaking on fast-flowing rivers is another popular activity. The (5)….. whitewater refers (6)........ the burbling foam created when fast-moving water spills over and around rocks or other (7)….. Whitewater enthusiasts maneuver their boats around rocks, logjams and other natural obstacles. If the current and obstacles (8)…… a passage (9)…. difficult to navigate, a canoeist might make a portage, or carry the canoe (10)…..  land for a short distance, thereby avoiding the danger."

5. The (5)….. whitewater refers

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.

   Most languages have several levels of vocabulary that may be used by the same speakers. In English, at least three have been identified and described.

   Standard usage includes those words and expressions understood, used, and accepted by a majority of the speakers of a language in any situation regardless of the levels of formality. As such, these words and expressions are well defined and listed in standard dictionaries. Colloquialisms, on the other hand, are familiar words and idioms that are understood by almost all speakers of a language and used in informal speech or writing, but not considered acceptable for more formal situations. Almost all idiomatic expressions are colloquial language. Slang, however, refers to words and expressions understood by a large number of speakers but not accepted as appropriate formal usage by the majority. Colloquial expressions and even slang may be found in standard dictionaries but will be so identified. Both Colloquial usage and slang are more common in speech than in writing. Colloquial speech often passes into standard speech. Some slang also passes into standard speech, but other slang expressions enjoy momentary popularity followed by obscurity. In some cases, the majority never accepts certain slang phrases but nevertheless retains them in their collective memories. Every generation seems to require its own set of words to describe familiar objects and events.

   It has been pointed out by a number of linguists that three cultural conditions are necessary for the creation of a large body of slang expressions. First, the introduction and acceptance of new objects and situations in the society; second, a diverse population with a large number of subgroups; third, association among the subgroups and the majority population.

   Finally, it is worth noting that the terms "standard", "colloquial" and "slang" exist only as abstract labels for scholars who study language. Only a tiny number of the speakers of any language will be aware that they are using colloquial or slang expressions. Most speakers of English will, during appropriate situations, select and use all three types of expressions.

The word "them" refers to __________

Read the text below and decide which answer (A,B,C, or D) best fits each space.
In a world where 2 billion people live in homes that don't have light bulbs, technology holds  the key (1)_______ banishing poverty. Even the simplest technologies can transform lives and  save money. Vaccines, crops, computers and sources of solar energy can all reduce poverty in  developing countries. For example, cheap oral-rehydration therapy developed in Bangladesh  has dramatically cut the death (2) _______ from childhood diarrhoea. 
But even when such technologies exist, the depressing fact is that we can’t make them (3)  _______ for those who most need them. Solar panels, batteries and light bulbs are still beyond  the purse of many, but where they have been installed they change lives. A decent light in the evening gives children more time for homework and extends the productive day for adults.  Kenya has a thriving solar industry and six years ago Kenyan pioneers also (4) _______  connecting schools to the Internet via radio links. These people were fortunate (5) _______  being able to afford solar panels, radios and old computers. How much bigger would the  impact be if these things (6) _______ and priced specifically for poor people? Multinationals must become part of the solution, because (7)_______ they own around 60 per  cent of the world's technology, they seldom make products for poor customers. Of 1,223 new  drugs marketed worldwide from 1975 to 1996, for example, just 13 were for tropical diseases. People think those enterprises should do more to provide vital products such as medicines (8) _______ different prices around the world to suit (9) _______ people can afford.  Alternatively, they could pay a percentage of their profit towards research and development  for (10) _______. 

 Question 9: .....................

Read the passage and choose the best answer:

Synchronized swimming is a hybrid form of swimming, dance and figure skating which consists of swimmers (either individuals, duets, trios, teams or combos) performing a synchronized routine of elaborate and dramatic moves in the water, accompanied by music. Synchronized swimming demands advanced water skills, and requires strength, endurance, flexibility, grace, artistry and precise timing, not to mention exceptional breath control while upside down underwater.

Developed in the early 1900s in Canada, it is a sport performed almost exclusively by women, although there is some participation by men. In its early form it was sometimes known as “water ballet”.

It is a Summer Olympic Games sport. First demonstrated in 1952, it has been an official event since 1984. Olympic and World Championship competition is not currently open to men, but other international and national competitions allow male competitors. Both USA Synchro and Synchro Canada allow men to compete with women. In competition, competitors show off their strength, flexibility, and aerobic endurance required to perform difficult routines. Swimmers perform two routines for the judges, one technical and one free.

Another name of synchronized swimming is “water ballet”.

Read the text below and decide which answer (A,B,C, or D) best fits each space.
In a world where 2 billion people live in homes that don't have light bulbs, technology holds  the key (1)_______ banishing poverty. Even the simplest technologies can transform lives and  save money. Vaccines, crops, computers and sources of solar energy can all reduce poverty in  developing countries. For example, cheap oral-rehydration therapy developed in Bangladesh  has dramatically cut the death (2) _______ from childhood diarrhoea. 
But even when such technologies exist, the depressing fact is that we can’t make them (3)  _______ for those who most need them. Solar panels, batteries and light bulbs are still beyond  the purse of many, but where they have been installed they change lives. A decent light in the evening gives children more time for homework and extends the productive day for adults.  Kenya has a thriving solar industry and six years ago Kenyan pioneers also (4) _______  connecting schools to the Internet via radio links. These people were fortunate (5) _______  being able to afford solar panels, radios and old computers. How much bigger would the  impact be if these things (6) _______ and priced specifically for poor people? Multinationals must become part of the solution, because (7)_______ they own around 60 per  cent of the world's technology, they seldom make products for poor customers. Of 1,223 new  drugs marketed worldwide from 1975 to 1996, for example, just 13 were for tropical diseases. People think those enterprises should do more to provide vital products such as medicines (8) _______ different prices around the world to suit (9) _______ people can afford.  Alternatively, they could pay a percentage of their profit towards research and development  for (10) _______. 

Question 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 from 36 to 42.
A study was set up to examine the old marriage advice about whether it's more important to be happy or to be right. Couples therapists sometimes suggest that in an attempt to avoid constant arguments, spouses weigh up whether pressing the point is worth the misery of marital discord. The researchers from the University of Auckland noticed that many of their patients were adding stress to their lives by insisting on being right, even when it worked against their well-being.
The researchers then found a couple who were willing to record their quality of life on a scale of 1 to 10. They told the man, who wanted to be happy more than right, about the purpose of the study and asked him to agree with every opinion and request his wife had without complaint, even when he profoundly didn't agree. The wife was not informed of the purpose of the study and just asked to record her quality of life.
Things went rapidly downhill for the couple. The man's quality-of-life scores fell, from 7 to 3, over the course of the experiment. The wife's scores rose modestly, from 8 to 8.5, before she became hostile to the idea of recording the scores. Rather than creating harmony, the husband's agreeableness led to the wife becoming increasingly critical of what he did and said (in the husband's opinion). After 12 days he broke down, and the study was called off because of severe adverse outcomes."
The researchers concluded, shockingly, that humans need to be right and acknowledged as right, at least some of the time, to be happy. They also noted this was further proof that if given too much power, humans tend to "assume the alpha position and, as with chimpanzees, they become very aggressive and dangerous." It is often said that there can be no peace without justice, and that's true of domestic sphere.
Obviously the results are to be taken with extreme caution, since this was just one couple with who-knows-what underlying issues beforehand. But the study's chief author, Dr. Bruce Arroll, maintains that the question of happiness vs. rightness, theoretically, could be settled by scientific inquiry with a wider sample. "This would include a randomized controlled trial,” he says. "However, we would be reluctant to do the definitive study because of the concern about divorce."

Which of the following can be inferred from paragraph 5?

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.

   Traditionally in America, helping the poor was a matter for private charities or local governments. Arriving immigrants depended mainly on predecessors from their homeland to help them start a new life. In the late 19th and early 20th centuries, several European nations instituted public-welfare programs. But such a movement was slow to take hold in the United States because the rapid pace of industrialization and the ready availability of farmland seemed to confirm the belief that anyone who was willing to work could find a job.

   Most of the programs started during the Depression era were temporary relief measures, but one of the programs Social Security – has become an American institution. Paid for by deductions from the paychecks of working people, Social Security ensures that retired persons receive a modest monthly income and also provides unemployment insurance, disability insurance, and other assistance to those who need it. Social Security payments to retired persons can start at age 62, but many wait until age 65, when the payments are slightly higher. Recently, there has been concern that the Social Security fund may not have enough money to fulfill its obligations in the 21st century, when the population of elderly Americans is expected to increase dramatically. Policy makers have proposed various ways to make up the anticipated deficit, but a long-term solution is still being debated. In the years since Roosevelt, other American presidents have established assistance programs. These include Medicaid and Medicare; food stamps, certificates that people can use to purchase food; and public housing which is built at federal expense and made available to persons on low incomes. Needy Americans can also turn to sources other than the government for help. A broad spectrum of private charities and voluntary organizations is available. Volunteerism is on the rise in the United States, especially among retired persons. It is estimated that almost 50 percent of Americans over age 18 do volunteer work, and nearly 75 percent of U.S. households contribute money to charity.

The passage mainly discusses ______.

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.

   Supernovas are the most powerful and spectacular outbursts known in nature. What is called a Type II supernova is due to the collapse of a massive star, at least eight times as massive as the sun, that has used up its main nuclear fuel and produced a nickel-iron core. When this core can no longer support the pressure of the star’s outer layer, it collapses to form a neutron star of immense density. Over 2,500 million tons of neutron star packed into a matchbox. Its temperature is around 100,000 million degrees centigrade.

   Multitudes of neutrons are produced in the collapsed star, which pass directly through the star into space, and this release of neutrons causes the core to respond with a shock wave that moves outward.

   When it meets the material that is falling inward, the result is a catastrophic explosion. Sometimes most of the star’s material is blown away, leaving only a small, incredibly dense remnant that may be a neutron star or, in extreme cases, a black hole.

   A supernova is often more than 500 million times as luminous as the sun. A supernova remnant (SNR) may be detectable as a pulsar, an example of which is the Crab Nebula, known to be a remnant of the supernova observed in the year 1054. The 1987 supernova in the Large Cloud of Magellan had a low peak luminosity by supernova standards, only about 250 million times that of the sun. As its brightest the supernova shone as a star between magnitudes 2 and 3, even though it was 170,000 light-years away.

The author of this passage is most likely __________________ .