6级710分阅读

Passage oneThere are two main hypotheses when it comes to explaining the emergence of modern humans. The “Out of Africa” theory holds that homo sapiens burst onto the scene as a new species around 150,000 to 200,000 years ago in Africa and subsequently replaced archaic humans such as the Neanderthals. The other model, known as multi-regional evolution or regional continuity, posits far more ancient and diverse roots for our kind. Proponents of this view believe that homo sapiens arose in Africa some 2 million years ago and evolved as a single species spread across the Old World, with populations in different regions linked through genetic and cultural exchange.Of these two models, “Out of Africa,”which was originally developed based on fossil evidence, and supported by much genetic research, has been favored by the majority of evolution scholars. The vast majority of these genetic studies have focused on DNA from living populations, and although some small progress has been made in recovering DNA from Neanderthal that appears to support multi-regionalism, the chance of recovering nuclear DNA from early human fossils is quite slim at present. Fossils thus remain very much a part of the human origins debates.Another means of gathering theoretical evidence is through bones. Examinations of early modern human skulls from Central Europe and Australia dated to between 20,000 and 30,000 years old have suggested that both groups apparently exhibit traits seen in their Middle Eastern and Africa predecessors. But the early modern specimens from Central Europe also display Neanderthal traits, and the early modern Australians showed affinities to archaic Homo from Indonesia. Meanwhile, the debate among palaeoanthropologists continues, as supporters of the two hypotheses challenge the evidence and conclusions of each other.According to the passages, the multi-regional model posits far more diverse roots for our kindPassage twoSome people say that the study of liberal arts is a useless luxury we can not afford in hard times. Students, they argue, who do not develop salable skills will find it difficult to land a job upon graduation. But there is a problem in speaking of “salable skills.” What skills are salable? Right now, skills for making automobiles are not highly salable, but they have been for decades and might be again. Skills in teaching are not now as salable as they were during the past 20 years, and the population charts indicate they may not be soon again. Home construction skills are another example of varying salability, as the job market fluctuates. What’s more, if one wants to build a curriculum exclusively on what is salable, one will have to make the courses very short and change them very often, in order to keep up with the rapid changes in the job market. But will not the effort be in vain? In very few things can we be sure of future salability, and in a society where people are free to study what they want, and work where they want, and invest as they want, there is no way to keep supply and demand in labor in perfect accord.A school that devotes itself totally to salable skills, especially in a time of high unemployment, sending young men and women into the world armed with only a narrow range of skills, is also sending lambs into the lion’s den. If those people gain nothing more from their studies than supposedly salable skills, and can’t make the sale because of changes in the job market, they have been cheated. But if those skills were more than salable, if study gave them a better understanding of the world around them and greater adaptability in a changing world, they have not been cheated. They will find some kind of job soon enough. Flexibility, an ability to change and learn new things, is a valuable skill. People who have learned how to learn can learn outside of school. That is where most of us have learned to do what we do, not in school. Learning to learn is one of the highest liberal skills.According to the author, which of the following is more likely to get a job in times of highPassage threeA number of factors related to the voice reveal the personality of the speaker. The first is the broad area of communication, which includes passing on information by use of language, communication with a group or an individual, and specialized communication through performance. A person conveys thoughts and ideas through choice of words, by a tone of voice that is pleasant or unpleasant, gentle or harsh, by the rhythm that is inherent within the language itself, and by speech rhythms that are flowing and regular or uneven and hesitant, and finally, by the pitch and melody of the utterance. When one speaks before a group, his tone may indicate unsureness or fright, confidence or clam. At interpersonal levels, his tone may reflect ideas and feelings over and above the words chosen, or may belie it. Here the speaker’s tone can consciously or unconsciously reflect intuitive sympathy or antipathy, lack of concern or interest, fatigue,anxiety, enthusiasm or excitement, all of which are usually discernible by the acute listener. Public performance is a manner of communication that is highly specialized with its own techniques for obtaining effects by voice and/or gesture. The motivation derived from the text, and in the case of singing, the music, in combination with the performer’s skills, personality, and ability to create empathy will determine the success of artistic, political or pedagogic communication.Second, the voice gives psychological clues to a person’s self-image, perception of others, and emotional health. Self-image can be indicated by a tone of voice that is confident, shy, aggressive, outgoing, or high-spirited, to name only a few personality traits. Also the sound may give a clue to the facade or mask of that person, for example, a shy person hiding behind an overconfident front. How a speaker perceives the listener’s receptiveness, interest, or sympathy in any given conversation can drastically alter the tone of presentation, by encouraging or discouraging the speaker. Emotional health is evidenced in the voice by free and melodic sounds of the happy, by constricted and harsh sound of the angry, and by dull and lethargic qualities of the depressed.By saying “At interpersonal levels, his tone may reflect ideas and feeling over and above theWhy does the author mention “artistic, political or pedagogic communication” at the end of thePassage fourThe San Andreas Fault is a fracture at the congruence of two major plates of the earth’s crust, one of which supports most of the North American continent, and the other of which underlies the coast of California and the ocean floor of the Pacific. The fault originates about six hundred miles from the Gulf of California and runs north in an irregular line along the west coast to San Francisco, where it continues north for about two hundred more miles before angling into the ocean. In places, the trace of the fault is marked by a trench, or, in geological terms, a rift, and small ponds called sag ponds that dot the landscape. Its western side always moves north in relation to its eastern side. The total net slip along the San Andreas Fault and the length of time it has been active are matters of conjecture, but it has been estimated that, during the past fifteen million years, coastal California along the San Andreas Fault has moved about 190 miles in a northwesterly direction with respect to North American. Although the movement along the fault averages only a few inches a year, it is intermittent and variable. Some segments of the fault do not move at all for long periods of time, building up tremendous pressure that must be released. For this reason, tremors are not unusual along the San Andreas Fault, and some of them are classified as major earthquakes.It is worth nothing that the San Andreas Fault passes uncomfortably close to several major metropolitan areas, including Los Angeles and San Francisco. In addition, the San Andreas Fault has created smaller fault systems, many of which underlie the smaller towns and cities along the Californian Coast. For this reason, Californians have long anticipated the recurrence of what they refer to as the “Big One,” a destructive earthquake that would measure near 8 on the Richter scale, similar in intensity to those that occurred in 1857 and 1906. The effects of such a quake would wreak devastating effects in the life and property in the region. Unfortunately, as pressure continues to build along the fault, the likelihood of such an earthquake increases substantially.Passage fiveFor laymen ethnology is probably the most interesting of the biological science for the very reason that it concerns animals in their normal activities and therefore, if we wish, we can assess the possible dangers and advantages in our own behavioral roots. Ethnology also is interesting methodologically because it combines in new ways very scrupulous field observations with experimentations in laboratories.The field workers have had some handicaps in winning respect for themselves. For a long time they were considered as little better than amateur animal-watchers—certainly not scientists, since their facts were not gained by experimental procedures: they could not conform to the hard-and-fast rule that a problem set up and solved by one scientist must be tested by other scientists, under identical conditions and reaching identical results. Of course many situations in the lives of animals simply cannot be rehearsed and controlled in this way. The fall flocking of wild birds can’t be, or the homing of animals over long distances, or even details of spontaneous family relationship. Since these never can be reproduced in a laboratory, are they then not worth knowing about?The ethnologists who choose field work have got themselves out of this impasse by greatly refining the techniques of observing. At the start of project all the animals to be studied are live-trapped, marked individually, and released. Motion pictures, often in color, provide permanent records of their subsequent activities. Recording of the animals’voices by electrical sound equipment is considered essential, and the most meticulous notes are kept of all that occurs. Withthis material other biologists, far from the scene, later can verity the reports. Moreover, two field observers often go out together, checking each other’s observation right there in the field.Ethnology, the world, is derived from the Greek ethos, meaning the characteristic traits or features which distinguish a group –any particular group of people or, in biology, a group of animals such as a species. Ethnologists have the intention of studying “the whole sequence of acts which constitute an animal’s behavior.” In abridged dictionaries ethnology is sometimes defined simply as “the objective study of animal behavior,” and ethnologists do emphasize their wish to eliminate myths.“The field workers have had some handicaps in winning respect for themselves.” This sentenceAccording to the explanation of the scientific rule of experiment in the passage, “hard-and-fast”The meaning of the underlined words in “details of spontaneous family relationships”can bePassage sixCan electricity cause cancer? In a society that literally runs on electric power, the very idea seems preposterous. But for more than a decade, a growing hand of scientists and journalists has pointed to studies that seem to link exposure to electromagnetic fields with increased risk of leukemia and other malignancies. The implications are unsettling, to say the least, since everyone comes into contact with such fields, which are generated by everything electrical, from power lines and antennas to personal computers and microwave ovens. Because evidence on the subject is inconclusive and often contradictory, it has been hard to decide whether concern about the health effects of electricity is legitimate.Now the alarmists have gained some qualified support from the U.S. Environmental Protection Agency. In the executive summary of a new scientific review, released in draft from late last week, the EPA has put forward what amounts to the most serious government warning to date. The agency tentatively concludes that scientific evidence “suggest a causal link” between extremely low-frequency electromagnetic fields—those having very long wavelengths—and leukemia, lymphoma and brain cancer. While the report falls short of classifying ELE fields as probable carcinogens, it does identify the common 60-hertz magnetic field as “a possible, but not proven, cause of cancer in humans.”The report is no reason to panic — or even to lose sleep. If there is a cancer risk, it is a small one. The evidence is still so controversial that the draft stirred a great deal of debate within the Bush Administration, and the EPA released it over strong objections from the Pentagon and the White House.At the heart of the debate is a simple and well understood physical phenomenon: when an electric current passes through a wire, it generates an electromagnetic field that exerts forces on surrounding objects. Foe many years, scientists dismissed any suggestion that such forces might be harmful, primarily because they are so extraordinarily weak.Doubles about weak, so-called nonionizing radiation began to grown in 1979, when a study of cancer rates among Colorado schoolchildren found that those who lived near power lines had two to three times as great a chance of developing cancer. The link seemed so unlikely that when power companies paid to have the original study replicated, most scientists expected the results to be negative. In fact, the subsequent study supported the original findings, which have since been buttressed by reports showing increased cancer rates among electrical workers.While many experts still express skepticism, there has been a definite shift of attitude in the scientific community about the possible health effects of electromagnetic fields, as a recent series in Science magazine made clear.“In a society that literally runs on electric power, the very idea seems preposterous.” What doesWhat is the author’s attitude towards the conclusion of scientists that the exposure toThe meaning of the underlined words in “While the report falls short of classifying ELE fields as。