15000 bài tập tách từ đề thi thử môn Tiếng Anh có đáp án (Phần 2)

I had never been to Denmark before, so when I set out to catch the ferry in early May, I little

suspected that by the end of the trip I'd have made such lasting friendships. Esjberg is a (23) ________ port for a cyclist's arrival, where tourist information can be obtained and money changed. A cycle track leads (24) ________ town and down to Ribe, where I spent my first night. The only appointment I had to keep was a meeting with a friend who was flying out in June. I wanted to use my time well, so I had planned a route which would include several small islands and various parts of the countryside.

In my (25) ________, a person travelling alone sometimes meets with unexpected hospitality, and this trip was no (26) ________. On only my second day, I got into conversation with a cheerful man who turned out to be the local baker. He insisted that I should join his family for lunch, and, while we were eating, he contacted his daughter in Odense. Within minutes, he had (27) ________ for me to visit her and her family. Then I was sent on my way with a fresh loaf of bread to keep me going and the feeling that this would turn out to be a wonderful holiday.

DESERTIFICATION

Desertification is the degradation of once-productive land into unproductive or poorly productive land. Since the first great urban-agricultural centers in Mesopotamia nearly 6,000 years ago, human activity has had a destructive impact on soil quality, leading to gradual desertification in virtually every area of the world. 

It is a common misconception that desertification is caused by droughts. Although drought does make land  more  vulnerable,  well-managed  land  can  survive  droughts  and  recover,  even  in  arid  regions.  Another mistaken belief is that the process occurs only along the edges of deserts. In fact, it may take place in any arid or  semiarid  region,  especially  where  poor  land  management  is  practiced.  Most  vulnerable,  however,  are  the transitional  zones  between  deserts  and  arable  land;  wherever  human  activity  leads  to  land  abuse  in  these fragile marginal areas, soil destruction is inevitable. 

[1]  Agriculture  and  overgrazing  are  the  two  major  sources  of  desertification.  [2]  Large-scale  farming requires  extensive  irrigation,  which  ultimately  destroys  lands  by  depleting  its  nutrients  and  leaching  minerals into the topsoil. [3] Grazing is especially destructive to land because, in addition to depleting cover vegetation, herds of grazing mammals also trample the fine organic particles of the topsoil, leading to soil compaction and

erosion. [4] It takes about 500 years for the earth to build up 3 centimeters of topsoil. However, cattle ranching and agriculture can deplete as much as 2 to 3 centimeters of topsoil every 25 years - 60 to 80 times faster than it can be replaced by nature. 

Salination  is  a  type  of  land  degradation  that  involves  an  increase  in  the  salt  content  of  the  soil.  This usually occurs as a result of improper irrigation practices. The greatest Mesopotamian empires- Sumer, Akkad and  Babylon-  were  built  on  the  surplus  of  the  enormously  productive  soil  of  the  ancient  Tigris-  Euphrates alluvial  plain.  After  nearly  a  thousand  years  of  intensive  cultivation,  land  quality  was  in  evident  decline.  In response, around 2800 BC the Sumerians began digging the huge Tigris-Euphrates canal system to irrigate the exhausted soil. A temporary gain in crop yield was achieved in this way, but over-irrigation was to have serious and unforeseen consequences. From as early as 2400 BC we find Sumerian documents referring to salinization as a soil problem. It is believed that the fall of the Akkadian Empire around 2150 BC may have been due to a catastrophic failure in land productivity; the soil was literally turned into salt. Even today, four thousand years later,  vast  tracks  of  salinized  land  between  the  Tigris  and  Euphrates  rivers  still  resemble  rock-hard  fields  of snow.

Soil  erosion  is  another  form  of  desertification.  It  is  a  self-reinforcing  process;  once  the  cycle  of degradation begins, conditions are set for continual deterioration. As the vegetative cover begins to disappear, soil becomes more vulnerable to raindrop impact. Water runs off instead of soaking in to provide moisture for plans. This further diminishes plan cover by leaching away nutrients from the soil. As soil quality declines and runoff  is  increased,  floods  become  more  frequent  and  more  severe.  Flooding  washes  away  topsoil,  the  thin, rich, uppermost layer of the earth’s soil, and leaves finer underlying particles more vulnerable to wind erosion. Topsoil contains the earth’s greatest concentration of organic matter and microorganisms, and is where most of the earth’s land-based biological activity  occurs.  Without this fragile  coat of nutrient-laden material, plan life cannot exist. An extreme case of its erosion is found in the Sahel, a transitional zone between the Sahara Desert and  the  tropical  African  rain  forests;  home  to  some  56  million  people.  Overpopulation  and  overgrazing  have opened  the  hyperarid  land  to  wind  erosion,  which  is  stripping  away  the  protective  margin  of  the  Sahel,  and causing  the  desert  to  grow  at  an  alarming  rate.  Between  1950  and  1975,  the  Sahara  Desert  spread  100 kilometers southward through the Sahel. 

 (1) Iron production was revolutionized in the early eighteenth century when coke was first used instead of charcoal for refining iron ore. Previously the poor quality of the iron had restricted its use in architecture to items such as chains and tie bars for supporting arches, vaults, and walls. With the improvement in refining ore, it  was  now  possible  to  make  cast-iron  beams,  columns,  and  girders.  During  the  nineteenth  century  further advances were made, notably Bessemer’s process for converting iron into steel, which made the material more commercially viable.

(2)  Iron  was  rapidly  adopted  for  the  construction  of  bridges,  because  its  strength  was  far  greater  than that of stone or timber, but its use in the architecture of buildings developed more slowly. By 1800 a complete internal  iron  skeleton  for  buildings  had  been  developed  in  industrial  architecture  replacing  traditional  timber beams, but it generally remained concealed. Apart from its low cost, the appeal of iron as a building material lay in its strength, its resistance to fire, and its potential to span vast areas. As a result, iron became increasingly popular as a structural material for more traditional styles of architecture during the nineteenth century, but it was invariably concealed.

(3)  Significantly,  the  use  of  exposed  iron  occurred  mainly  in  the  new  building  types  spawned  by  the Industrial Revolution: in factories, warehouses, commercial offices, exhibition hall, and railroad stations, where its  practical  advantages  far  outweighed  its  lack  of  status.  Designers  of  the  railroad  stations  of  the  new  age explored  the  potential  of  iron,  covering  huge  areas  with  spans  that  surpassed  the  great  vaults  of  medieval churches and cathedrals. Paxton’s Crystal Palace, designed to house the Great Exhibition of 1851, covered an area of 1.848 feet by  408 feet in prefabricated units of  glass set in iron frames. The Paris  Exhibition of 1889 included both  the widest span and the  greatest height achieved so far with the Halle  Des Machines, spanning 362 feet, and the Eiffel Tower 1,000 feet high. However, these achievements were mocked by the artistic elite of Paris as expensive and ugly follies. Iron, despite its structural advantages, had little aesthetic status. The use of an exposed iron structure in the more traditional styles of architecture was slower to develop.

(1) Interest is the sum charged for borrowing money for a fixed period of time. Principal is the term used for the money that is borrowed, and the rate of interest is the percent per year of the principal charged for its use. Most of the profits for a bank are derived from the interest that they charge for the use of their own or their depositor’s money.

(2) All problems in interest may be solved by using one general equation that may be stated as follows:

Interest = Principal X Rate X Time

(3) Any one of the four quantities – that is, interest, principal, rate, or time – may be found when the other three are known. The time is expressed in years. The rate is expressed as a decimal fraction. Thus, 6 percent interest means six cents charged for the use of $1 of principal borrowed for one year. Although the time may be less than, equal to, or greater than one year, most applications for loans are for periods of less than one year. For purpose of computing interest for short periods, the commercial year or 360 days is commonly used, but when large sums of money are involved, exact interest is computed on the basis of 365 days.

 (1) The protozoans, minute, aquatic creatures each of which consists of a single cell of protoplasm, constitute a classification of the most primitive forms of animal life. They are fantastically diverse, but three major groups may be identified on the basis of their motility. The Mastigophora have one or more long tails, which they use to project themselves forward. The Ciliata, which use the same basic means for locomotion as the Mastigophora, have a larger number of short tails. The Sarcodina, which include amoebae, float or row themselves about on their crusted bodies.

(2) In addition to their form of movement, several other features discriminate among the three groups of protozoans. For example, at least two nuclei per cell have been identified in the Ciliata, usually a large nucleus that regulates growth but decomposes during reproduction, and a smaller one that contains the genetic code necessary to generate the large nucleus.

(3) Protozoans are considered animals because, unlike pigmented plants to which some protozoans are otherwise almost identical, they do not live on simple organic compounds. Their cell demonstrates all of the major characteristics of the cells of higher animals.

(4) Many species of protozoans collect into colonies, physically connected to each other and responding uniformly to outside stimulate. Current research into this phenomenon, along with investigations carried out with advanced microscopes may necessitate a redefinition of what constitutes protozoans, even calling into question the basic premise that they have only one cell. Nevertheless, with the current data available, almost 40,000 species of protozoans have been identified. No doubt, as the technology improves our methods of observation, better models of classification will be proposed.

Reading to oneself is a modern activity which was almost unknown to the scholars of the classical and medieval worlds, while during the fifteenth century the term “reading” undoubtedly meant reading aloud. Only during the nineteenth century did silent reading become commonplace.

    One should be wary, however, of assuming that silent reading came about simply because reading aloud was a distraction to others. Examinations of factors related to the historical development of silent reading have revealed that it became the usual mode of reading for most adults mainly because the tasks themselves changed in character.

    The last century saw a steady gradual increase in literacy and thus in the number of readers. As the number of readers increased, the number of potential listeners declined and thus there was some reduction in the need to read aloud. As reading for the benefit of listeners grew less common, so came the flourishing of reading as a private activity in such public places as libraries, railway carriages and offices, where reading aloud would cause distraction to other readers.

    Towards the end of the century, there was still considerable argument over whether books should be used for information or treated respectfully and over whether the reading of materials such as newspapers was in some way mentally weakening. Indeed, this argument remains with us still in education. However, whatever its virtues, the old shared literacy culture had gone and was replaced by the printed mass media on the one hand and by books and periodicals for a specialised readership on the other.

    By the end of the twentieth century, students were being recommended to adopt attitudes to books and to use reading skills which were inappropriate, if not impossible, for the oral reader. The social, cultural and technological changes in the century had greatly altered what the term “reading” implied.

The Sun today is a yellow dwarf star. It is fueled by thermonuclear reactions near its center that convert hydrogen to helium. The Sun has existed in its present state for about four billion six hundred million years and is thousands of times larger than the Earth.

    By studying other stars, astronomers can predict what the rest of the Sun’s life will be like. About five billion years from now, the core of the Sun will shrink and become hotter. The surface temperature will fall. The higher temperature of the center will increase the rate of thermonuclear reactions. The outer regions of the Sun will expand approximately 35 million miles, about the distance to Mercury, which is the closest planet to the Sun. The Sun will then be a red giant star. Temperatures on the Earth will become too high for life to exist.

    Once the Sun has used up its thermonuclear energy as a red giant, it will begin to shrink. After it shrinks to the size of the Earth, it will become a white dwarf star. The Sun may throw off huge amounts of gases in violent eruptions called nova explosions as it changes from a red giant to a white dwarf.

    After billions of years as a white dwarf, the Sun will have used up all its fuel and will have lost its heat. Such a star is called a black dwarf. After the Sun has become a black dwarf, the Earth will be dark and cold. If any atmosphere remains there, it will have frozen over the Earth’s surface.

(1) The protozoans, minute, aquatic creatures each of which consists of a single cell of protoplasm, constitute a classification of the most primitive forms of animal life. They are fantastically diverse, but three major groups may be identified on the basis of their motility. The Mastigophora have one or more long tails, which they use to project themselves forward. The Ciliata, which use the same basic means for locomotion as the Mastigophora, have a larger number of short tails. The Sarcodina, which include amoebae, float or row themselves about on their crusted bodies.

(2) In addition to their form of movement, several other features discriminate among the three groups of protozoans. For example, at least two nuclei per cell have been identified in the Ciliata, usually a large nucleus that regulates growth but decomposes during reproduction, and a smaller one that contains the genetic code necessary to generate the large nucleus.

(3) Protozoans are considered animals because, unlike pigmented plants to which some protozoans are otherwise almost identical, they do not live on simple organic compounds. Their cell demonstrates all of the major characteristics of the cells of higher animals.

(4) Many species of protozoans collect into colonies, physically connected to each other and responding uniformly to outside stimulae. Current research into this phenomenon, along with investigations carried out with advanced microscopes may necessitate a redefinition of what constitutes protozoans, even calling into question the basic premise that they have only one cell. Nevertheless, with the current data available, almost 40,000 species of protozoans have been identified. No doubt, as the technology improves our methods of observation, better models of classification will be proposed.

 (1) It was the first photograph that I had ever seen, and it fascinated me. I can remember holding it at every angle in order to catch the flickering light from the oil lamp on the dresser. The man in the photograph was unsmiling, but his eyes were kind. I had never met him, but I felt that I knew him. One evening when I was looking at the photograph, as I always did before I went to sleep, I noticed a shadow across the man’s thin face. I moved the photograph so that the shadow lay perfectly around his hollow cheecks. How different he looked!

(2) That night I could not sleep, thinking about the letter that I would write. First, I would tell him that I was eleven years old, and that if he had a little girl my age, she could write to me instead of him. I knew that he was a very busy man. Then I would explain to him the real purpose of my letter. I would tell him how wonderful he looked with the shadow that I had seen across his photograph, and I would most carefully suggest that he grow whiskers.

(3) Four months later when I met him at the train station near my home in Westfield, New York, he was wearing a full beard. He was so much taller than I had imagined from my tiny photograph.

(4) “Ladies and gentlemen,” he said, “I have no speech to make and no time to make it in. I appear before you that I may see you and that you may see me.” Then he picked me right up and kissed me on both cheeks. The whiskers scratched. “Do you think I look better, my little friend?” he asked me.

(5) My name is Grace Bedell, and the man in the photograph was Abraham Lincoln.

Very few people in the modern world obtain their food supply by hunting and gathering in the natural environment surrounding their homes. This method of harvesting from nature’s provision is the oldest subsistence strategy, and has been practiced for at least the last two million years. It was, indeed, the only way to obtain food until rudimentary farming and the domestication of wild animals were introduced about 10,000 years ago.

    Because hunter-gatherers have fared poorly in comparison with their agricultural cousins, their numbers have dwindled, and they have been forced to live in marginal environments, such as deserts and arctic wastelands. In higher latitudes, the shorter growing season has restricted the availability of plant life. Such conditions have caused a greater independence on hunting, and along the coasts and waterways, on fishing. The abundance of vegetation in the lower latitudes of the tropics, on the other hand, has provided a greater opportunity for gathering a variety of plants. In short, the environmental differences have restricted the diet and have limited possibilities for the development of subsistence societies. Contemporary hunter-gatherers may help us understand our prehistoric ancestors. We know from observation of modern hunter-gatherers in both Africa and Alaska that society based on hunting and gathering must be very mobile. While the entire community camps in a central location, a smaller party harvests the food within a reasonable distance from the camp. When the food in the area is exhausted, the community moves on to exploit another site. We also notice seasonal migration on patterns evolving for most hunter-gatherers, along with a strict division of labor between sexes. These patterns of behavior may be similar to those practiced by mankind during the Paleolithic Period.