15000 bài tập tách từ đề thi thử môn Tiếng Anh có đáp án (Phần 84)

As heart disease continues to be the number-one killer in the United States, researchers  have become increasingly interested in identifying the potential risk factors that trigger heart attacks. High-fat diets and “life in the fast lane” have long been known to contribute to 5 the high incidence of heart failure. But according to new studies, the list of risk factors may be significantly longer and quite surprising.

          Heart failure, for example, appears to have seasonal and temporal 10 patterns. A higher percentage of heart attacks occur in cold weather, and more people experience heart failure on Monday than on any other day of the week. In addition, people are more susceptible to heart attacks in the first few hours after waking. Cardiologists first observed this morning phenomenon

in the mid-1980, and have since 15 discovered a number of possible causes. An early-morning rise in blood pressure, heart rate, and concentration of heart stimulating hormones, plus a reduction of blood flow to the heart, may all contribute to the higher incidence of heart attacks between the hours of 8:00 A.M. and 10:00 A.M.

          In other studies, both birthdays and bachelorhood have been implicated as risk factors. Statistics reveal that heart attack rates increase significantly for both females and males in the few days immediately preceding and following their birthdays. And unmarried men are more 25 at risk for heart attacks than their married counterparts. Though stress is thought to be linked in some way to all of the aforementioned risk factors, intense research continues in the hope of further comprehending why and how heart failure is triggered

Aging is the process of growing old. It occurs eventually in every living thing provided, of course, that an illness or accident does not kill it prematurely. The most familiar outward signs of aging may be seen in old people, such as the graying of the hair and the wrinkling of the skin. Signs of aging in a pet dog or cat include loss of playfulness and energy, a decline in hearing and eyesight, or even a slight graying of the coat. Plants age too, but the signs are much harder to detect.

Most body parts grow bigger and stronger, and function more efficiently during childhood. They reach their peak at the time of maturity, or early adulthood. After that, they begin to decline. Bones, for example, gradually become lighter and more brittle. In the aged, the joints between the bones also become rigid and more inflexible. This can make moving very painful.

          All the major organs of the body show signs of aging. The brain, for example, works less efficiently, and even gets smaller in size. Thinking processes of all sorts are slowed down. Old people often have trouble in remembering recent events.

One of the most serious changes of old age occurs in the arteries, the blood vessels that lead from the heart. They become thickened and constricted, allowing less blood to flow to the rest of body. This condition accounts, directly or indirectly, for many of the diseases of the aged. It may, forexample, result in heart attack.

          Aging is not a uniform process. Different parts of the body wear out at different rates. There are great differences among people in their rate of aging. Even the cells of the body differ in the way they age. The majority of cells are capable of reproducing themselves many times during the course of a lifetime. Nerve cells and muscle fibers can never be replaced once they wear out.

          Gerontologists - scientists who study the process of aging-believe this wearing out of the body is controlled by a built-in biological time-clock. They are trying to discover how this clock works so that they can slow down the process. This could give man a longer life and a great number of productive years.

ORESUND BRIDGE

          Imagine driving along a bridge that is so long that you can't even see the other end. The Oresund Bridge, one of the longest bridges in the world, (61)________so far ahead into the distance that you can't even tell where the blue of the water (62) ________ the blue of the sky.

          The Oresund Bridge is an amazing example of modern engineering design that links the Scandinavian countries of Denmark and Sweden. It is 8 kilometers long and was (63) ________in July 2000. It crosses the Flinte Channel, the chilly waterway (64) ________the two countries.

          At one stage the bridge turns into a tunnel under the sea. This tunnel is also a record breaker in its own right as it is the longest road and rail tunnel in the world. The engineers built an artificial island near the Danish coast that (65) ________support part of the bridge structure, as well as being the point at which the road disappears underground, before coming out in Copenhagen, the capital of Denmark.

Mickey Mantle was one of the greatest baseball players of all time. He played for the New York Yankees in their years of glory. From the time Mantle began to play professionally in 1951 to his last year in 1968, baseball was the most popular game in the United States. For many people, Mantle symbolized the hope, prosperity, and confidence of America at that time.

          Mantle was a fast and powerful player, a “switch-hitter” who could bat both right-handed and left-handed. He won game after game, one World Series championship after another, for his team. He was a wonderful athlete, but this alone cannot explain America’s fascination with him.

          Perhaps it was because he was a handsome, red-haired country boy, the son of a poor miner from Oklahoma. His career, from the lead mines of the West to the heights of success and fame, was a fairy-tale version of the American dream. Or perhaps it was because America always loves a “natural”: a person who wins without seeming to try, whose talent appears to come from an inner grace. That was Mickey Mantle.

          But like many celebrities, Mickey Mantle had a private life that was full of problems. He played without complaint despite constant pain from injuries. He lived to fulfill his father’s dreams and drank to forget his father’s early death.

          It was a terrible addiction that finally destroyed his body. It gave him cirrhosis of the liver and accelerated the advance of liver cancer. Even when Mickey Mantle had turned away from his old life and warned young people not to follow his example, the destructive process could not be stopped. Despite a liver transplant operation that had all those who loved and admired him hoping for a recovery, Mickey Mantle died of cancer at the age of 63

Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

          The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

          In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world's weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

          The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

The United States has many different types of families. While most American families are traditional, (81) ________a father, a mother and one or more children, 22 percent of all American families in 1998 were headed by one parent, usually a woman. In a few families in the United States, there are no children. These (82) ________couples may believe that they would not make good parents; they may want freedom from responsibilities of childbearing; or, perhaps they (83) ________ physically able to have children. Other families in the United States have one adult who is a stepparent. A stepmother or stepfather is a person who joins a family by marrying a father or a mother.

          Americans (84) ________and accept these different types of families. In the United States people have right to privacy and Americans do not believe in telling other Americans what type of family group they must belong to. They respect each other’s choices regarding family groups. Families are very important (85) ________ Americans.

          Perhaps it was his own lack of adequate schooling that inspired Horace Mann to work so hard for the important reforms in education that he accomplished. While he was still a boy, his father and older brother died, and he became responsible for supporting his family. Like most of the children in his town, he attended school only two or three months a year. Later, with the help of several teachers, he was able to study law and became a member of the Massachusetts bar, but he never forgot those early struggles.

          While serving in Massachusetts legislature, he signed a historic education bill that set up a state board of education. Without regret, he gave up his successful legal practice and political career to become the frst secretary of the board. There he exercised an enormous influence during the critical period of reconstruction that brought into existence the American graded elementary school as substitute for the older distinct school system. Under his leadership, the curriculum was restructured, the school year was increased to a minimum of six months, and mandatory schooling was extended to age sixteen. Other important reforms included the establishment of state normal schools for teacher training, institutes for in-service teacher education, and lyceums for adult education. He was also instrument in improving salaries for eachers and creating school libraries.

          Mann’s ideas about school reform were developed and distributed in twelve annual reports to the state of Massachusetts that he wrote during his tenure as secretary of education. Considered quite radical at the time, the Massachusetts reforms later served as a model for the nation. Mann was recognized as the  father of public education

          Psychologist have debated a long time about whether a child’s upbringing can give it the ability to do outstandingly well. Some think that it is impossible to develop genius and say that it is simply something a person is born with. Others, however , argue that the potential for great achievement can be develop. The truth lies somewhere between these two extremes. It seems very obvious that being born with the right qualities from gifted parents will increase a child’s ability to do well. However, this ability will be fully realized only with the right upbringing and opportunities. As one psychologist says, “ To have a fast car, you need both a good engine and fuel.’’ Scientists have recently assessed intelligence, achievement, and ability in 50 sets of identical twins that were separated shortly birth and brought up by different parents. They found that achievement was based on intelligence, and later influenced by the child’s environment. One case involving very intelligent twins was quoted. One of the twins received a normal upbringing, and performed well. The other twin, however, was brought up by extremely supportive parents and given every possible opportunity to develop its abilities. That twin, thought starting out with the same degree of intelligence as the other, performed even better. This case reflects the general principle of intelligence and ability. The more favorable the environment, the more a child’s intelligence and ability are developed.

          However, there is no link between intelligence and socioeconomic level of a child’s family. In other words, it does not matter how poor or how rich a family is , as this does not affect the intelligence. Gifted people can not be created by supportive parents, but they can be developed by them. One professor of music said that outstanding musicians usually started two or three years earlier than ordinary performers, often because their parents had recognized their ability. These musicians then needed at least ten years’ hard work and training in order to reach the level they were capable of attaining. People who want to have very gifted children are given the following advice:

          - Marry an intelligent person.

          - Allow children to follow their own interests rather than the interests of the parents.

          - Start a child’s education early but avoid pushing the child too hard.

          - Encourage children to play; for example, playing with musical instrument is essential for a child who wants to become an outstanding musician.

Nowadays people are more aware that wildlife all over the world is in (31) ________. Many species of animals are threatened, and could easily become (32) ________ if we do not make an effort to protect them. There are many reasons for this. In some cases animals are hunted for their fur or for other valuable parts of their bodies. Some birds, such as parrots, are caught (33) ________, and sold as pets. For many animals and birds, the problem is that their habitatsthe place where they live-is disappearing. More land is used for farm, for houses and industry, and there are fewer open spaces than there once were. Farmers use powerful chemicals to help them grow better crops, but these chemicals pollute the environment and (34) ________ wildlife. The most successful animals on Earth, human beings, will soon be the only ones (35) ________ unless we can solve this problem.

          Although speech is the most advanced form of communication, there are many ways of communicating without using speech. Signals, signs, symbols, and gestures may be found in every known culture. The basic function of signal is to impinge upon the environment in such a way that it attracts attention, as, for example, the dots and dashes of a telegraph circuit. Coded to refer to speech, the potential for communication is very great. Less adaptable to the codification of words, signs also contain meaning in and of themselves. A stop sign or a barber pole conveys meaning quickly and conveniently. 

          Symbols are more difficult to describe than either signals or signs because of their intricate relationship with the receiver’s cultural perceptions. In some cultures, applauding in a theater provides performers with an auditory symbol of approval. Gestures such as waving and handshaking also communicate certain cultural messages.

          Although signals, signs, symbols, and gestures are very useful, they do have a major disadvantage in communication. They usually do not allow ideas to be shared without the sender being directly adjacent to the receiver. Without an exchange of ideas, interaction comes to a halt. As a result, means of communication intended to be used for long distances and extended periods must be based upon speech. To radio, television, and the telephone, one must add fax, paging systems, electronic mail, and the Internet, and no one doubts but that there are more means of communication on the horizon.