15000 bài tập tách từ đề thi thử môn Tiếng Anh có đáp án (Phần 76)

In the past, both men and women were expected to be married at quite young ages. Marriages were generally arranged by parents and family, with their children having little chance to say no in the matter. In the past, it was not surprising to find that a bride and groom had only just met on the day of their engagement or marriage.

In modern Vietnam, this has changed completely as people choose their own marriage-partners based on love, and in consideration primarily to their own needs and wants. Moreover early marriage is quite illegal.

The traditional Vietnamese wedding is one of the most important of traditional Vietnamese occasions. Regardless of westernization, many of the age-old customs practiced in a traditional Vietnamese wedding continue to be celebrated by both Vietnamese in Vietnam and overseas, often combining both western and eastern elements. Besides the wedding ceremony, there is also an engagement ceremony which takes place usually half a year or so before the wedding. The number of guests in attendance at these banquets is huge, usually in

the hundreds. Several special dishes are served. Guests are expected to bring gifts, often money, which the groom and bride at one point in the banquet will go from table to table collecting.

Herman Melville, an American author best known today for his novel Moby Dick, was actually more popular during his lifetime for some of his other works. He traveled extensively and used the knowledge gained during his travels as the basis for his early novels. In 1837, at the age of eighteen, Melville signed as a cabin boy on a merchant ship that was to sail from his Massachusetts home to Liverpool, England. His experiences on this trip served as a basis for the novel Redburn (1849). In 1841 Melville set out on a whaling ship headed for the South Seas. After jumping ship in Tahiti, he wandered around the islands of Tahiti and Moorea. This South Sea island sojourn was a backdrop to the novel Omoo (1847). After three years away from home, Melville joined up with a U.S. naval frigate that was returning to the eastern United States around Cape Horn. The novel White-Jacket (1850) describes this lengthy voyage as a navy seaman.

With the publication of these early adventure novels, Melville developed a strong and loyal following among readers eager for his tales of exotic places and situations. However, in 1851, with the publication of Moby Dick, Melville's popularity started to diminish. Moby Dick, on one level the saga of the hunt for the great white whale, was also a heavily symbolic allegory of the heroic struggle of man against the universe. The public was not ready for Melville's literary metamorphosis from romantic adventure to philosophical symbolism. It is ironic that the novel that served to diminish Melville's popularity during his lifetime is the one for which he is best known today.

The handling and delivery of mail has always been a serious business, underpinned by the trust of the public in requiring timeliness, safety, and confidentiality. After early beginnings using horseback and stagecoach, and although cars and trucks later replaced stagecoaches and wagons, the Railway Mail Service still stands as one of America’s most resourceful and exciting postal innovations. This service began in 1832, but grew slowly until the Civil War. Then from 1862, by sorting the mail on board moving trains, the Post Office Department was able to decentralize its operations as railroads began to crisscross the nation on a regular basis, and speed up mail delivery. This service lasted until 1974. During peak decades of service, railway mail clerks handled 93% of all non-local mail and by 1905 the service had over 12,000 employees.

Railway Post Office trains used a system of mail cranes to exchange mail at stations without stopping. As a train approached the crane, a clerk prepared the catcher arm which would then snatch the incoming mailbag in the blink of an eye. The clerk then booted out the outgoing mailbag. Experienced clerks were considered the elite of the Postal Service’s employees, and spoke with pride of making the switch at night with nothing but the curves and feel of the track to warn them of an upcoming catch. They also worked under the greatest pressure and their jobs were considered to be exhausting and dangerous. In addition to regular demands of their jobs they could find themselves the victims of train wrecks and robberies.

As successful as it was, “mail-on-the-fly” still had its share of glitches. If they hoisted the train’s catcher arm too soon, they risked hitting switch targets, telegraph poles or semaphores, which would rip the catcher arm off the train. Too late, and they would miss an exchange.

Sunlight is solar energy. Sunlight is needed for growing plants that you eat to get energy. Sunlight is also used to make clean electricity. Burning fossil fuels to make electricity pollutes our atmosphere and rivers. Fossil fuels are expensive and limited sources of energy. Nuclear fission is used to create enormous amount of heat and electricity. However, nuclear fission forms dangerous radioactive waste.

Sunlight offers many ways to get energy. A window can allow warm sunlight into your room. Solar water-heating systems can use sunlight to warm the water for your home, swimming pool and school. Sunlight also warms the Earth and causes wind. Electricity can be made by wind generators.

Photovoltaic, or PV system use a type of material that converts sunlight into electricity. PV systems can power your air conditioner or a satellite like the International Space Station. PV systems are also used to run a calculator, recharge cell phone, or even power lightweight cars.

Sunlight is also changed into electricity by concentrating solar power or CSP systems. CSP systems have mirrors that focus the sunlight. The concentrated sunlight turns water into steam which turns a turbine that is connected to an electric generator. A CSP system usually uses sunlight to make steam. CSP power plants can store large amount of heat. The stored heat is used to make electricity at night. During cloud days, many CSP plants can also burn natural gas to provide the heat that is used to turn water into steam.

Sunlight provides the energy needed to grow plants and make large amount of environmentally friendly heat and electricity. Solar energy can provide power today and for a long time in the future.

In most discussions of cultural diversity, attention has focused on visible, explicit aspects of culture, such as language, dress, food, religion, music, and social rituals. Although they are important, these visible expressions of culture, which are taught deliberately and learned consciously, are only the tip of the iceberg of culture. Much of culture is taught and learned implicitly, or outside awareness. Thus, neither cultural insiders nor cultural outsiders are aware that certain “invisible” aspects of their culture exist.

Invisible elements of culture are important to us. For example, how long we can be late before being impolite, what topics we should avoid in a conversation, how we show interest or attention through listening behaviour, what we consider beautiful or ugly- these are all aspects of culture that we learn and use without being aware of it. When we meet other people whose invisible cultural assumptions differ from those we have learned implicitly, we usually do not recognize their behaviour as cultural in origin.

Differences in invisible culture can cause problems in cross-cultural relations. Conflicts may arise when we are unable to recognize others’ behavioural differences as cultural rather than personal. We tend to misinterpret other people’s behaviour, blame them, or judge their intentions or competence without realizing that we are experiencing cultural rather than individual differences.

Formal organizations and institutions, such as schools, hospitals, workplaces, governments, and the legal system are collection sites for invisible cultural differences. If the differences were more visible, we might have less misunderstanding. For example, if we met a man in a courthouse who was wearing exotic clothes, speaking a language other than ours, and carrying food that looked strange, we would not assume that we understood his thoughts and feelings or that he understood ours. Yet when such a man is dressed similarly to us, speaks our language, and does not differ from us in other obvious ways, we may fail to recognize the invisible cultural differences between us. As a result, mutual misunderstanding may arise.

Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction.

Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth.

The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.

Martin Luther King, Jf., is well- known for his work in civil rights and for his many famous speeches, among which is his moving “ I have a dream” speech. But fewer people know much about King’s childhood. M.L., as he was called, was born in 1929 in Atlanta, Georgia, at the home of his maternal grandfather. M.L.’s grandfather purchased their home on Auburn Avenue in 1909, twenty years before M.L was born. His grandfather allowed the house to be used as a meeting place for a number of organizations dedicated to the education and social advancement of blacks. M.L. grew up in the atmosphere, with his home being used as a community gathering place, and was no doubt influenced by it.

M.L.’s childhood was not especially eventfully. His father was a minister and his mother was a musician. He was the second of three children, and he attended all black schools in a black neighborhood. The neighborhood was not poor, however. Auburn Avenue was an area of banks, insurance companies, builders, jewelers, tailors, doctors, lawyers, and other businesses and services. Even in the face of Atlanta’s segregation, the district thrived. Dr. King never forgot the community spirit he had known as a child, nor did he forget the racial prejudice that was a huge barrier keeping black Atlantans from mingling with whites.

A pioneering study by Donald Appleyard made the astounding discovery that a sudden increase in the volume of traffic through an area affects people in the way that a sudden increase in crime does. Appleyard observed this by finding three blocks of houses in San Francisco that looked much alike and had the same kind of middle-class and working-class residents, with approximately the same ethnic mix. The difference was that only 2,000 cars a day ran down Octavia Street (LIGHT street, in Appleyard’s terminology) while Gough Street (MEDIUM street) was used by 8,000 cars daily, and Franklin Street (HEAVY street) had around 16,000 cars a day. Franklin Street often had as many cars in an hour as Octavia had in a day.
          Heavy traffic brought with it danger, noise, fumes and soot, directly, and trash secondarily. That is, the cars didn’t bring in much trash, but when trash accumulated, residents seldom picked it up. The cars, Appleyard determined, reduced the amount of territory residents felt responsible for. Noise was a constant intrusion into their homes. Many Franklin Street residents covered their doors and windows and spent most of their time in the rear of their houses. Most families with children had already left.
          Conditions on Octavia Street were much different. Residents picked up trash. They sat on their front steps and chatted with neighbors. They had three times as many friends and twice as many acquaintances as the people on Franklin.
          On Gough Street, residents said that the old feeling of community was disappearing as traffic increased. People were becoming more and more preoccupied with their own lives. A number of families had recently moved and more were considering. Those who were staying expressed deep regret at the destruction of their community.

Dinosaurs were reptiles that lived during a period of earth’s history called the Mesozoic Era, which is known as the Age of Reptiles. The first dinosaurs appeared more than 200 million years ago. For many millions of years, they dominated the land with their huge size and strength. Then about 65 million years ago, they died out rather suddenly, never to reemerge.
          The word dinosaur comes from two Greek words meaning “terrible lizard”. Dinosaurs were not lizards, but their appearance could be truly terrifying. The biggest ones weighed more than ten times as much as a mature elephant and nearly equaled the size of most modern—day whales. The famous kinds of dinosaurs, including the brontosaur and tyrannosaurus, reached 80 to 90 feet in length. Not all dinosaurs were giants, however, some were actually no larger than a chicken.
          Scientists still do not know what caused dinosaur to disappear. One theory involves a change in the earth’s climate. It is believed that temperature dropped significantly towards the end of the Cretaceous Period. Too large to hibernate and not having fur or feathers for protection, it is possible that the climate became too chilly for dinosaurs. In contrast, other species having protection, such as the mammals and birds, were able to survive

The cause of tooth decay is acid, which is produced by bacteria in the mouth. The acid removes minerals from tooth enamel, allowing tooth decay to begin; the saliva in your mouth encourages remineralization and neutralizes the acid. The rate at which bacteria in the mouth produce acid depends on the amount of plaque on the teeth, the composition of the microbial flora, and whether the bacteria of the plaque have been "primed" by frequent exposure to sugar. To keep your teeth healthy, a regular dental hygiene program should be followed.
Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of bacteria in the mouth and thus reduces tooth decay. It also makes the surfaces of the teeth more accessible, enabling saliva to neutralize acid and remineralize lesions. If fluoride is present in drinking water when teeth are forming, some fluoride is incorporated into the enamel of the teeth, making them more resistant to attack by acid. Fluoride toothpaste seems to act in another way, by promoting the remineralization of early carious lesions.
In addition to a regular dental hygiene program, a good way to keep your teeth healthy is to reduce your intake of sweet food. The least cavity-causing way to eat sweets is to have them with meals and not between. The number of times you eat sweets rather than the total amount determines how much harmful acid the bacteria in your saliva produce. But the amount of sweets influences the quality of your saliva. Avoid, if you can, sticky sweets that stay in your mouth a long time. Also try to brush and floss your teeth after eating sugary foods. Even rinsing your mouth with water is effective. Whenever possible, eat foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that scrape off plaque, acting as a toothbrush. Cavities can be greatly reduced if these rules are followed when eating sweets.