15000 bài tập tách từ đề thi thử môn Tiếng Anh có đáp án (Phần 18)

Vitamins, taken in tiny doses, are a major group of organic compounds that regulate the mechanisms by which the body converts food into energy. They should not be confused with minerals, which are inorganic in their makeup. Although in general the naming of vitamins followed the alphabetical order of their identification, the nomenclature of individual substances may appear to be somewhat random and disorganized. Among the 13 vitamins known today, five are produced in the body. Because the body produces sufficient quantities of some but not all vitamins, they must be supplemented in the daily diet. Although each vitamin has its specific designation and cannot be replaced by another compound, a lack of one vitamin can interfere with the processing of another. When a lack of even one vitamin in a diet is continual, a vitamin deficiency may result.

The best way for an individual to ensure a necessary supply of vitamins is to maintain a balanced diet that includes a variety of foods and provides adequate quantities of all the compounds. Some people take vitamin supplements, predominantly in the form of tablets. The vitamins in such supplements are equivalent to those in food, but an adult who maintains a balanced diet does not need a daily supplement. The ingestion of supplements is recommended only to correct an existing deficiency due to unbalanced diet, to provide vitamins known to be lacking in a restricted diet, or to act as a therapeutic measure in medical treatment. Specifically, caution must be exercised with fat-soluble substances, such as vitamins A and D, because, taken in gigantic doses, they may present a serious health hazard over a period of time.

Geothermal energy is natural heat from the interior of the Earth that is converted to heat buildings and generate electricity. The idea of harnessing Earth’s internal heat is not new. As early as 1904 , geothermal power was used in Italy . Today, Earth’s natural internal heat is being used to generate electricity in 21 countries , including Russia, Japan, New Zealand, Iceland, Mexico, Ethiopia, Guatemala, EI Salvador, the Philippines, and the United States .Total worldwide production is approaching 9,000 MW (equivalent to nine large modern coal-burning or nuclear power plants)-double the amount in 1980 .Some 40 million people today receive their electricity from geothermal energy at a cost competitive with that of other energy sources. In EI Salvador , geothermal energy is supplying 30% of the total electric energy used. However, at the global level, geothermal energy supplies less than 0,15%of the total energy supply.

Geothermal energy may be considered a nonrenewable energy source when rates of extraction are greater than rates of natural replenishment. However, geothermal energy has its origin in the natural heat production within Earth , and only a small fraction of the vast total resource base is being utilized today. Although most geothermal energy production involves the tapping of high heat sources, people are also using the low-temperature geothermal energy of groundwater in some applications.

Geothermal Systems

The average heat flow from the interior of the Earth is very low, about 0,06% W/m2.This amount is trivial compared with the 177 W/m2from solar heat at the surface in the United States. However, in some areas, heat flow is sufficiently high to be useful for producing energy . For the most part, areas of high heat flow are associated with plate tectonic boundaries. Oceanic ridge systems (divergent plate boundaries) and areas where mountains are being uplifted and volcanic island arcs are forming (convergent plate boundaries) are areas where this natural heat flow is anomalously high. One such region is located in the western, United States, where recent tectonic and volcanic activity has occurred.

 On the basis of geological criteria, several types of hot geothermal systems (with temperatures greater than about 800C , or 1760F)have been defined, and the resource base is larger than that of fossil fuels and nuclear energy combined. A common system for energy development is hydrothermal convection, characterized by the circulation of steam and / or hot water that transfers heat from depths to the surface.

Geothermal Energy and the Environment

 The environmental impact of geothermal energy may not be as extensive as that of other sources of energy , but it can be considerable. When geothermal energy is developed at a particular site, environmental problems include on-site noise, emissions of gas, and disturbance of the land at drilling sites, disposal sites, roads and pipelines, and power plants. Development of geothermal energy does not require large-scale transportation of raw materials or refining of chemicals, as development of fossil fuels does. Furthermore, geothermal energy does not produce the atmospheric pollutants associated with burning fossil fuels or the radioactive waste associated with nuclear energy. However, geothermal development often does produce considerable thermal pollution from hot waste-waters, which may be saline or highly corrosive, producing disposal and treatment problem.

 Geothermal power is not very popular in some locations among some people. For instance, geothermal energy has been produced for years on the island of Hawaii, where active volcanic processes provide abundant near surface heat. There is controversy, however, over further exploration and development .Native Hawaiians and others have argued that the exploration and development of geothermal energy degrade the tropical forest as developers construct roads, build facilities , and drill wells.

In addition, religious and cultural issues in Hawaii relate to the use of geothermal energy. For example, some people are offended by using the “breath and water of Pele” ( the volcano goddess) to make electricity. This issue points out the importance of being sensitive to the values and cultures of the people where development is planned.

Future of Geothermal energy

 At present, geothermal energy supplies only a small fraction of the electrical energy produced in the United States. However, if developed, known geothermal resources in the United States could produce about 20,000 MW which is about 10% of the electricity needed for the western states. Geohydrothermal resources not yet discovered could conservatively provide four times that amounts (approximately 10% of total U.S electric capacity). About equivalent to the electricity produced from water power today.

Although management principles have been implemented since ancient times, most management scholars trace the beginning of modern management thought back to the early 1900s, beginning with the pioneering work of Frederick Taylor (1856-1915) Taylor was the first person to study work scientifically. He is most famous for introducing techniques of time and motion study, differential piece rate systems, and for systematically specializing the work of operating employees and managers. Along with other pioneers such as Frank and Lillian Gilbreth, Taylor set the stage, labeling his philosophy and methods “scientific management’. At that time, his philosophy, which was concerned with productivity, but which was often misinterpreted as promoting worker interests at the expense of management, was in marked contrast to the prevailing industrial norms of worker exploitation.

The time and motion study concepts were popularized by Frank and Lillian Gilbreth. The Gilbreths had 12 children. By analyzing his children’s dishwashing and bedmaking chores, this pioneer efficiency expert, Frank Gilbreth, hit on principles whereby workers could eliminate waste motion. He was memorialized by two of his children in their 1949 book called “Cheaper by the Dozen”.

The Gilbreth methods included using stop watches to time worker movements and special tools (cameras and special clocks) to monitor and study worker performance, and also involved identification of “therbligs” (Gilbreth spelled backwards) – basic motions used in production jobs. Many of these motions and accompanying times have been used to determine how long it should take a skilled worker to perform a given job. In this way an industrial engineer can get a handle on the approximate time it should take to produce a product or provide a service. However, use of work analysis in this way is unlikely to lead to useful results unless all five work dimensions are considered: physical, psychological, social, cultural, and power.

Perhaps better known than the Cullinan Diamond is the Hope Diamond, a valuable and blue gem with a background of more than 300 years as a world traveler.The 112-carat blue stone later became the Hope Diamond was mined in India sometime before the middle of the seventeenth century and was first known to be owned by Shah Jahan, who built the Taj Mahal in memory of his beloved wife. From India, the celebrated blue stone has changed hands often, moving from location to location in distant corners of the world.

In the middle of the seventeenth century, a trader from France named Jean Baptiste Tavernier acquired the large blue diamond, which was rumored to have been illegally removed from a temple Tavemier returned to France with the big blue gem, where the stone was purchased by the Sun King Louis XIV. Louis XIV had it cut down from 112 to 67 carats to make its shape symmetrical and to maximize its sparkle. The newly cut diamond, still huge by any standards, was passed down through the royal family of France, until it arrived in the hands of Louis XVI and Marie Antoinette. During the French Revolution, Louis XVI and his wife met their fate on the guillotine in 1793, and the big blue diamond disappeared from public sight.

The diamond somehow managed to get from France to England, where banker Henry Hope purchased it from a gem dealer early in the nineteenth century. The huge blue stone was cut into a 45.5-carat oval, and at this point it took on the name by which it is known today. The diamond stayed in the Hope family for around a century, when deep indebtedness brought on by a serious gambling habit on the part of one of Henry Hope's heirs forced the sale of the diamond.

From England, the Hope Diamond may have made its way into the hands of the Sultan of Turkey; whatever route it took to get there, it eventually went on to the United States when American Evelyn Walsh McLean purchased it in 1911. Mrs. McLean certainly enjoyed showing the diamond off guests in her home were sometimes astounded to notice the huge stone embellishing the neck of Mrs. McLean’s Great Dane as the huge pet trotted around the grounds of her Washington, D.C. home. The Hope Diamond later became the property of jeweler Harry Winston, who presented the stunning 45.5- carat piece to the Smithsonian in 1958. The Hope Diamond is now taking a well-earned rest following its rigorous travel itinerary and is on display at the Smithsonian Institution in Washington, D.C., where it has been since 1958.

Children learn to construct language from those around them. Until about the age of three, children tend to learn to develop their language by modeling the speech of their parents, but from that time on, peers have a growing influence as models for language development in children. It is easy to observe that, when adults and older children interact with younger children, they tend to modify their language to improve children communication with younger children, and this modified language is called caretaker speech.

Caretaker speech is used often quite unconsciously; few people actually study how to modify language when speaking to young children but, instead, without thinking, find ways to reduce the complexity of language in order to communicate effectively with young children. A caretaker will unconsciously speak in one way with adults and in a very different way with young children. Caretaker speech tends to be slower speech with short, simple words and sentences which are said in a higher-pitched voice with exaggerated inflections and many repetitions of essential information. It is not limited to what is commonly called baby talk, which generally refers to the use of simplified, repeated syllable expressions, such as ma-ma, boo-boo, bye-bye, wa-wa, but also includes the simplified sentence structures repeated in sing-song inflections. Examples of these are expressions such as “ say bye-bye” or “where’s da-da?”

Caretaker speech serves the very important function of allowing young children to acquire language more easily. The higher-pitched voice and the exaggerated inflections tend to focus the small child on what the caretaker is saying, the simplified words and sentences make it easier for the small child to begin to comprehended, and the repetitions reinforce the child’s developing understanding. Then, as a child’s speech develops, caretakers tend to adjust their language in the response to the improved language skills, again quite unconsciously. Parents and older children regularly adjust their speed to a level that is slightly above that of a younger child; without studied recognition of what they are doing, these caretakers will speak in one way to a one-year-ago and in a progressively more complex way as the child reaches the age of two or three.

An important point to note is that the function covered by caretaker speech, that of assisting a child to acquire language in small and simple steps, is an unconsciously used but extremely important part of the process of language acquisition and as such is quite universal. It is not merely a device used by English-speaking parents. Studying cultures where children do not acquire language through caretaker speech is difficult because such cultures are not difficult to find. The question of why caretaker speech is universal is not clear understood; instead proponents on either side of the nature vs. nature debate argue over whether caretaker speech is a natural function or a learned one. Those who believe that caretaker speech is a natural and inherent function in humans believe that it is human nature for children to acquire language and for those around them to encourage their language acquisition naturally; the presence of a child is itself a natural stimulus that increases the rate of caretaker speech develops through nurturing rather than nature argue that a person who is attempting to communicate with a child will learn by trying out different ways of communicating to determine which is the most effective from the reactions to the communication attempts; apparent might, for example, learn to use speech with exaggerated inflections with a small child because the exaggerated inflections do a better job of attracting the child’s attention than do more subtle inflections. Whether caretaker speech results from nature or nurture, it does play an important and universal role in child language acquisition.

Although noise, commonly defined as unwanted sound, is a widely recognized form of pollution, it is very difficult to measure because the discomfort experienced by different individuals is highly subjective and, therefore, variable. Exposure to lower levels of noise may be slightly irritating, whereas exposure to higher levels may actually cause hearing loss. Particularly in congested urban areas, the noise produced as a by product of our advancing technology causes physical and psychological harm, and detracts from the quality of life for those who are exposed to it.

Unlike the eyes, which can be covered by the eyelids against strong light, the ear has no lid, and is, therefore, always open and vulnerable; noise penetrates without protection.

Noise causes effects that the hearer cannot control and to which the body never becomes accustomed. Loud noises instinctively signal danger to any organism with a hearing mechanism, including human beings. In response, heartbeat and respiration accelerate, blood vessels constrict, the skin pales, and muscles tense. In fact, there is a general increase in functioning brought about by the flow of adrenaline released in response to fear, and some of these responses persist even longer than the noise, occasionally as long as thirty minutes after the sound has ceased.

Because noise is unavoidable in a complex, industrial society, we are constantly responding in the same way that we would respond to danger. Recently, researchers have concluded that noise and our response may be much more than an annoyance. It may be a serious threat to physical and psychological health and well-being, causing damage not only to the ear and brain but also to the heart and stomach. We have long known that hearing loss is America’s number one nonfatal health problem, but now we are learning that some of us with heart disease and ulcers may be victims of noise as well. Fetuses exposed to noise tend to be overactive, they cry easily, and they are more sensitive to gastrointestinal problems after birth. In addition, the psychic effect of noise is very important. Nervousness, irritability, tension, and anxiety increase, affecting the quality of rest during sleep, and the efficiency of activities during waking hours, as well as the way that we interact with each other.

Martin Luther King, Jr., is well known for his work in civil rights and for his many famous speeches, among them 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, the Reverend A.D. Williams, purchased their home on Auburn Avenue in 1909, twenty years before M.L. was born. The Reverend Williams, an eloquent speaker, played an important role in the community since so many people’s lives centered around the church. He allowed his church and his home 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 this 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 eventful. 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 the main artery through a prosperous neighborhood that had come to symbolize achievement for Atlanta’s black people. It was an area of banks, insurance companies, builders, jewelers, tailors, doctors, lawyers, and other black-owner, black-operated 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 seemingly insurmountable barrier that kept black Atlanta from mingling with whites.

CUTTING THE APRON STRINGS

 There is substantial evidence that students going off to college have changed over the years. For one thing, studies show that they are emotionally closer to their parents and their parents to them. One thing that means is that they depend on each other more for happiness. It puts a burden on children for parents to use their children as vehicles for their own happiness- although today’s young people seem complicit in this arrangement, perhaps because they’ve known no other way-even if it creates anxiety in the children. That’s one reason parents like to be involved in their children’s college experiences, and colleges have had to devise novel ways of getting parents off campus when they transport their kids to school.

 There’s also evidence that students today seem to be choosing schools with reference to proximity to home. The closer a student is to home, the easier it is to bring the laundry home and to land in your old bed with tea and sympathy when you have the sniffles. And the easier it is for parents to visit you at university whenever the mood strikes. The amount of visiting parents do is far more than in generations past.

 But in a real sense, students don’t really leave their parents behind. Their parents go to college right along with them - in their front pockets. That is, the parents are a speed dial away by cell phone. This, of course, significantly reduces independence. A student doesn’t get the chance to solve minor problems on his own - he just calls Mom or Dad. A student has initial problems getting along with a roommate? A roommate doesn’t do laundry as often as the other roommate wishes? A student gets a C grade on her first paper? Instead of absorbing the negative information and figuring out how to resolve the problem or how to do better, the call gets made to home, where Mom or Dad solves the problem, often by calling the school administration. This kind of behavior is, sadly, commonplace today and is a mark of the lack of coping skills among students because all the lumps and bumps have been taken out of life for them until now.

 In addition to being tethered to parents, incoming freshmen are now very heavily connected by cell phone to classmates from high school, who are presumably at other colleges. So there isn’t the great impetus to mix and venture forth to meet new people, to get out of one’s comfort zone, to get drawn into new experiences, that has traditionally marked the beginning of freshman year. The laws of physics still apply, and it is difficult to be meeting new people and seeking novel experiences while you are talking to your old pals.

Researchers in the field of psychology have found that one of the best ways to make an important decision, such as choosing a university to attend or a business to invest in, involves the utilization of a decision worksheet. Psychologists who study optimization compare the actual decisions made by people to theoretical ideal decisions to see how similar they are. Proponents of the worksheet procedure believe that it will yield optimal, that is, the best decisions. Although there are several variations on the exact format that worksheets can take, they are all similar in their essential aspects.

 Worksheets require defining the problem in a clear and concise way and then listing all possible solutions to the problem. Next, the pertinent considerations that will be affected by each decision are listed, and the relative importance of each consideration or consequence is determined. Each consideration is assigned a numerical value to reflect its relative importance. A decision is mathematically calculated by adding these values together. The alternative with the highest number of points emerges as the best decision.

 Since most important problems are multifaceted, there are several alternatives to choose from, each with unique advantages and disadvantages. One of the benefits of a pencil and paper decision-making procedure is that it permits people to deal with more variables than their minds can generally comprehend and remember. On the average, people can keep about seven ideas in their minds at once. A worksheet can be especially useful when the decision involves a large number of variables with complex relationships. A realistic example for many college students is the question “What will I do after graduation?” A graduate might seek a position that offers specialized training, pursue an advanced degree, or travel abroad for a year.

 A decision-making worksheet begins with a succinct statement of the problem that will also help to narrow it. It is important to be clear about the distinction between long-range and immediate goals because long-range goals often involve a different decision from short-range ones. Focusing on long-range goals, a graduating student might revise the question above to “What will I do after graduation that will lead to a successful career?”

The National Automobile Show in New York has been one of the top auto shows in the United States since 1900. On November 3 of that year, about 8,000 people looked over the “ horseless carriages”. It was opening day and the first opportunity for the automobile industry to show off its wares to large crowd; however, the black-tie audience treated the occasion more as a social affair than as sales extravaganza. It was also on the first day of this show that William Mckinley became the first U.S Present to ride in a car.

The automobile was not invented in the United States. That distinction belongs to Germany. Nikolaus Otto built the first practical internal-combustion engine there in 1876. Then, German engineer Karl Benz built what are regarded as the first modern automobiles in the mid-1880s. But the United States pioneered the merchandising of the automobile. The auto show proved to be an effective means of getting the public excited about automotive products.

By happenstance, the number of people at the first New York show equaled the entire car population of the United States at that time. In 1900, 10 million bicycles and an unknown number of horse-drawn carriages provided the prime means of personal transportation. Only about 4,000 cars were assembled in the United States in 1900, and only a quarter of those were gasoline powered. The rest ran on steam or electricity.

After viewing the cars made by forty car makers, the show’s audience favored electric cars because they were quiet. The risk of a boiler explosion turned people away from streamers, and the gasoline-powered cars produced smelly fumes. The Duryea Motor Wagon Company, which launched the American auto industry in 1895, offered a fragrant additive designed to mask the smells of the naphtha that is burned. Many of the 1900 models were cumbersome – the Gas mobile, the Franklin, and the Orient, for example, steered with a tiller like a boat instead of with a steering wheel. None of them was equipped with an automatic starter.

These early model cars were practically handmade and were not very dependable. They were basically toys of the well-to-do. In fact, Woodrow Wilson, then a professor at Princeton University and later President of the United States, predicted that automobiles would cause conflict between the wealthy and the poor. However, among the exhibitors at the 1900 show was a young engineer named Henry Ford. The cars he exhibited at the 1900 show apparently attracted no special notice. But before the end of the decade, he would revolutionize the automobile industry with his Model T Ford. The Model T, first produced in 1909, featured a standardized design and a steamlined method of production – the assembly line. Its lower costs made it available to the mass market.

Cars at the 1900 show ranged in price from 1,000 dollars to 1,500 dollars, or roughly 14,000 dollars to 21,000 in today’s prices. By 1913, the Model T was selling for less than 300 dollars , and soon the price would drop even further. “I will build cars for the multiudes,” Ford said, and he kept his promise.