单选题The frequent ______ from cold to warm weather this spring have caused much illness.

单选题 There are three general methods people use to explain and understand their world, beliefs, pseudoscience, and science. What are beliefs? Well, simply put, beliefs are what you believe to be true. In this first method of interpreting man and the world, certain people proved the information about how the world works. Their teachings are beyond question. Their followers accept these beliefs because they want to accept them, not because of scientific evidence. Some examples are religions, such as Christianity. Christians believe in one God. who created the universe and all that is in it. They believe that this God is active in history, guiding and teaching His people. Like many religions, Christianity provides a number of specific moral rules and principles that make up an important part of its teachings. Superstitions, such as Fung Shui, are also common examples of beliefs. Pseudoscience, also called fake science, is any body or knowledge, methodology, belief, or practice that claims to be scientific or is made to appear scientific, but is actually not. In pseudoscience, people accept opinions, or choose to believe certain facts while intentionally ignoring others, resulting in a false understanding of things and events. Beliefs in magic, monsters, and ghosts fall into this category. Both Chinese Qigong and Indian Yoga are very good physical exercises that can help their practitioners keep fit, but when some magical power, they are turning Qigong or Yoga into pseudoscience. Many people follow pseudoscience be-cause belief in magic or mysterious powers is entertaining. Astrology has millions of followers all around the world, not because it helps them deal with the world in any better way, only because it is just fun. Of the three methods, only science provides a rational way of understanding the world. It does not provide a moral system as religion does and it may not always be as entertaining as pseudoscience sometimes is, but it is the only method that requires constant testing of facts, beliefs and ideas, resulting in changing theories as we get new information. Science teaches us to draw conclusions based on evidence and it also teaches us that some evidence is stronger than other evidence, and how to judge the evidence. Through our study of science, we learn to accept uncertainty, to question facts and theories, and to search constantly for truth. Most of us use all three methods in different proportions to view our world. Some scientists believe in theories without supporting evidence. And the scientific method is often used for unscientific purposes. But science is the only method that is constantly changing. It does not depend on the teachings of one man. Each scientist builds on the work of others and his findings, in turn, are used by others to increase our knowledge of the world.

单选题 The goal of this training program is to raise children with a sense of responsibility and necessary courage to be willing to take on challenges in life.

单选题Early in the sixteenth century, Francis Bacon proposed that science consisted in the elevation of the authority of experiment and observation over that of reason, intuition, and convention. Bacon thought that as more and more reliable and precise particular facts accumulate, they can be classified and generalized, resulting in an ever-expanding hierarchy of useful "axioms". This is what he meant by "induction". Although many people today continue to regard the collection of facts and their arrangement by induction into theories as the heart of scientific method, Bacon's conception of what facts and theories are and of the relationship between them was hopelessly unrealistic even in his own time. The most important early scientific discoveries — such as those made by Galileo about the movement of the earth, by Keppler about the elliptical shape of planetary orbits, and later by Newton about the "force" of gravity — could never have been made if Bacon's rules had prevailed. Determined to avoid all premature speculations, Bacon proposed that data gathering be carried out by illiterate assistants with no interest in whether an experiment turned out one way or another. Plain facts, properly arranged, would automatically lead to certain knowledge of the universe. Nothing could be more misrepresentative of the actual problem-solving techniques of the scientific method. That plain facts do not speak for themselves is evident from Bacon's own acceptance of the errors contained in what appeared to be the most "obvious" of facts. For Bacon, that the earth did not move was a fact because it could be seen not to move; and for Bacon it was a fact that life was being spontaneously generated because maggots always developed in putrid flesh and frogs appeared after every rain. What is clear is that the great breakthroughs of Newton, Darwin, or Marx could never have been achieved solely on the basis of Baconian fact gathering. Facts are always unreliable without theories which guide their collection and which distinguish between superficial and significant appearances.

单选题Watch a baby between six and nine months old, and you will observe the basic concept of geometry being learned. Once the baby has mastered the idea that space is three dimensional, itreaches out and begins grasping various kinds of objects. It is then, from perhaps nine to fifteen months, that the concepts of sets and numbers are formed. So far, so good. But now an ominous development takes place. The nerve fibers in the brain insulate themselves in such a way that the baby begins to hear sounds very precisely. Soon it picks up language, and it is then brought into direct communication with adults. From this point on, it is usually downhill all the way for mathematics, because the child now becomes exposed to all the nonsense words and beliefs of the community into which it has been so unfortunate as to have been born. Nature, having done very well by the child to this point, having permitted it the luxury of thinking for itself for eighteen months, now abandons it to the arbitrary conventions and beliefs of society. But at least the child knows something of geometry and numbers; and it will always retain some memory of the early halcyon days, no matter what vicissitudes it may suffer later on. The main reservoir of mathematical talent in any society is thus possessed by children who are about two years old, children who have just learned to speak fluently.

单选题{{B}}Passage 3{{/B}} For scientists who study human evolution, fossil remains provide the only direct evidence of our ancient ancestors. Access to these paleoanthropological Rosetta stones, how- ever, is limited by protective curators who are often reluctant to lend the fragile fossils. And in the case of fossil skulls, nature preserves critical information in the largely in- accessible interior. But help is on the way. At the annual meeting of the American Association of Physical Anthropologists in Salt Lake City this past April, researchers discussed how medical imaging, virtual reality and computer-controlled modelling technologies get around these obstacles noninvasively. Three-dimensional medical imaging based on computed tomography (CT) scans was developed in the early 1980s. On a computer, surgeons could electronically remove the patient's soft tissue and then explore the virtual skull inside and out before operating. It wasn't long before Glenn Conroy of Washington University and his colleagues demonstrated that these same techniques could also be applied to fossils, in which sediments take the place of soft tissue. With advances in computer graphics and computational power, paleoanthropologists can now perform on their computers a wide range of investigations that are impossible to attempt on the original fossil. Missing features on one Side of the skull can be re-created by mirroring the preserved features (postmortem deformations can be similarly rectified) and tiny, hidden structures such as the inner ear can be magnified for closer examination. Moreover, as Christoph P. E. Zollikofer and Marcias Ponce de Leon of the University of Zurich and others have shown, anthropologists can reconstruct fragmented fossils on-screen. The standard repertoire of measurements can also be made virtually, in most cases with the same degree of accuracy afforded by handheld calipers. And with the creation of a virtual "endocast", brain volume can be determined reliably. In fact, Conroy's recent re- Search has revealed a major discrepancy between the estimated and actual brain volume of an early hominid called Stw 505 (or Mr. Pies). Conroy suspects that the estimated cranial capacity of some other fossils might also be incorrect--a hunch that, if substantiated, could have important implications for our understanding of brain evolution.

单选题It is these skills that ______ are being neglected in the arguments over ambiguity and the setting of guidelines for sound research practices.

单选题The growth of cell-phone users in the U.S. has tapered off from the breakneck pace of 50% annually in the late 1990s to what analysts project will be a 15% to 20% rise in 2002, and no more than that in 2003. To some extent, numerous surveys have found, slower growth in demand reflects consumer disillusionment with just about every aspect of cell-phone service—its reliability, quality, and notorious customer service. The cooling off in demand threatens to cascade through the industry: The big four U.S. cell-phone carders—Verizon Wireless, Cingular Wireless, AT&T Wireless, Sprint imperil their timetables for becoming profitable, not to mention their efforts to whittle down their mountains of debt. As the carders have begun to cut costs, wireless- equipment makers—companies such as Lucent, Nokia, and Ericsson—have been left with a market that's bound to be smaller than they had anticipated. Handset makers have been insulated so far, but they, too, face a nagging uncertainty. They'll soon introduce advanced phones to the U.S. market that will run on the new networks the carders are starting up over the next year or two. But the question then will be: Will Americans embrace these snazzy data features—and their higher costs—with the wild enthusiasm that Europeans and Asians have? Long before the outcome in clear, the industry will have to adopt a new mind-set. "In the old days, it was all about connectivity." says Andrew Cole, an analyst with wireless consultancy Adventis. Build the network, and customers will come. From now on, the stakes will be higher. The new mantra: Please customers, or you may not survive. To work their way out of this box, the carders are spending huge sums to address the problem. Much of Sprint PCS's $ 3.4 billion in capital outlays this year will be for new stations. And in fact, the new high-speed, high-capacity nationwide networks due to roll out later this year should help ease the calling-capacity crunch that has caused many consumer complaints. In the meantime, some companies are using better training and organization to keep customers happy. The nation's largest rural operator, Alltel (AT), recently reorganized its call centers so that a customer's query goes to the first operator who's available anywhere in the country, instead of the first one available in the customer's home area. That should cut waiting time to one minute from three to five minutes previously.

单选题Happy______they were, there was something missing.

单选题Over-cultivation and a long period of erosion has reduced the ______ of much of the country's farmland. A.sufficiency B.fertility C.prosperity D.mobility

单选题What is the ______ of going by boat when the plane costs no more and is quicker?

单选题We had come here to escape a ______ summer heat wave and to examine firsthand some of the park's problems.

单选题Main Street is the ______ stop for this bus route.

单选题The old man took a great______ in collecting stamps.

单选题You should ______ at least three days for the journey.

单选题If you would like to send a donation, you can______a cheque to the organization Feed the Children.

单选题The strong scent of Kate's perfume ______ the air in the small room. A. radiated B. permeated C. extracted D. dispersed

单选题To take part in a space flight would be an exciting______.

单选题When the revolutionary situation changes, revolutionary tactics must change______.