填空题Answer questions by referring to the following 3 passages. Note: Answer each question by choosing A, B or C and mark it on ANSWER SHEET 1. Some choices may be required more than once. A = Passage One B = Passage Two C= Passage Three In which passage ... can you build a relationship over a cup of tea? 21. ______ has caffeine been around for far longer than that in the form of tea? 22. ______ is the general result of caffeine to make people more alter and focused? 23. ______ is Britain the only European tea drinking culture? 24. ______ can we find without tea, the human race would not come so far and so fast? 25. ______ is caffeine also found in chocolate? 26. ______ can we find the arrival of coffee speeded everything up? 27. ______ is the coffee shops in China a symbol that coffee culture had come to China? 28. ______ can we find more than 90 percent of the world's population takes caffeine every day? 29. ______ can we see coffee houses were filled with people making plans, talking business and doing deals? 30. ______ Passage One Do you know what kind of people give drugs to their children? Do you still know where in the world people take drugs before going to work? The answers are simple — ordinary people, just about everywhere. And the drug in question is caffeine. Scientists estimate that over 90 percent of the world's population take caffeine daily. Adults drink it in tea and coffee. Children drink it in Coca Cola and similar soft drinks. It is also found in chocolate. As a result, most people in most places across the world at any one time are under the influence of the drug. Not surprisingly there have been many scientific investigations into the exact effects of caffeine. Most agree that it stimulates the nervous system and helps the body make efficient use of food energy. This is why many people across Asia drink tea with food and why Westerners often eat their meals with a cup of coffee. The general result of caffeine is to make people more alter and focused. Unlike alcohol, caffeine dose not change your behavior. But it dose increase your ability to do things. Passage Two Both tea and coffee were introduced to the West around 300 years ago. The effect of these new drinks was immediately. In London, coffee houses were filled with people making plans, talking business and doing deals. The coffee houses themselves later developed into London's financial center. And the deals done in the coffee houses were partly responsible for a rapid increase in British trade. History was moving in that direction anyway. But the arrival of coffee speeded everything up. Weinberg and Bealer back up their claims with scientific research which shows that frequent use of caffeine causes people to grow new brain cells. They also point to research which shows that people with caffeine in their system perform a range of tasks better than those without it. Without caffeine, would the human race come so far and so fast? Caffeine helped the West make a great leap forward a few hundred years ago. In China and Japan, it has been around for far longer than that in the form of tea. It could go back further that people realize. The Japanese tea ceremony might be an example of what anthropologists call "ceremonial chemistry". This is a practice amongst ancient and primitive peoples of taking mind altering drugs as part of religious festivities. Passage Three Tea has around 50% less caffeine in it than coffee, and there are real differences between tea and coffee drinking cultures. In Britain, the European tea drinking culture, workers have been known to do on strike to demand a ten-minute tea break in the working day. Tea gives people enough caffeine to help put up with a boring job or help them recover after a hard day. It is something to share with friends. You build relationships over a cup of tea. But you get results with coffee. Coffee gives you that extra dose of caffeine. It is associated with staying up all night to Finish a business plan or study for exams. When Starbucks opened their first coffee shops in China they got a lot of publicity. Much of this was because another fashionable foreign business had come to China. But maybe it was a symbol that coffee culture had arrived. From now on, everything was going to get faster. It is worth thinking about. But don't think for too long. There is much work to be done. Drink up and get busy.

填空题 Supermarket shoppers have never been more spoilt for choice. But just when we thought traditional systems of selective farming had created the most tempting array of foods money can buy, we are now being presented with the prospect of genetically created strains of cabbages, onion, tomato, potato and apple. It may not tickle the fancy of food purists but it fires the imagination of scientists, last week they discovered that the classic Parisian mushroom contains just the properties that, when genetically mixed with a wild strain of mushroom from the Sonora desert in California, could help it grow en masse while at the same time providing it with the resilience of the wild strain.66. ______ "We have found a way of increasing the success rate from one to 90 per cent." This is just one of the many products that, according to skeptics, are creating a generation of "Frankenfoods". The first such food that may be consumed on a wide scale is a tomato which bas been genetically manipulated so that it does not soften as it ripens.67. ______ Critics say that the new tomato—which cost $25 million to research—is designed to stay on supermarket shelves for longer. It has a ten-day life span. Not surprisingly, every-hungry US is leading the search for these forbidden fruit. By changing the genes of a grapefruit, a grower from Texas has created a sweet, red, thin-skinned grapefruit expected to sell at a premium over its California and Florida competitors. For chip fanatics who want to watch their waist-lines, new high-starch, low-moisture potatoes that absorb less fat when fried have been created, thanks to a gene from intestinal bacteria. The scientists behind such new food argue that genetic engineering is simply an extension of animal and plant breeding methods and that by broadening the scope of the genetic changes that can be made, sources of food are increased. Accordingly, they argue, this does not inherently lead to foods that are less safe than those developed by conventional techniques. But if desirable genes are swapped irrespective of species barriers, could things spiral out of control? "Knowledge is not toxic," said Mark Cantley, head of the biotechnology unit at the Organisation for Economic Co-operation and Development, "It has given us a far greater understanding of how living systems work at a molecular level and there is no reason for people to think that scientists and farmers should use that knowledge to do risky things." Clearly, financial incentive lies behind the development of these bigger, more productive foods. But we may have only ourselves to blame. In the early period of mass food commerce, food varieties were developed by traditional methods of selective breeding to suit the local palate. But as suppliers started to select and preserve plant variants that had larger fruit, consumer expectations rose, leading to the development of the desirable clones. Still, traditionalists and gourmets in Europe are fighting their development.68. ______ Even in the pre-packaged US, where the slow-softening tomato will soon be reaching supermarkets, 1,500 American chefs have lent their support to the Pure Food Campaign which calls for the international boycott of genetically engineered foods until more is known about the consequences of the technology and reliable controls have been introduced. In the short term, much of the technology remains untested and in the long term the consequences for human biology are unknown. Questions have arisen over whether new proteins in genetically modified food could cause allergies in some people.69. ______ Then there are the vegetarians who may be consuming animal non-vegetable proteins in what they think is a common tomato, or the practicing Jew who unknowingly consumes a fruit that has been enhanced with a pig's gene. As yet, producers are under no obligation to label "transgenetic" products. Environmentalists worry that new, genetically engineered plants may damage natural environment. A genetically engineered pest-resistant strain of plant that contacts with a native strain, for example, could turn them into virulent weeds beyond chemical control. Animal welfare groups worry about the quality of life of farm animals manipulated so that they produce more meat, milk, and eggs but which may suffer physical damage in the process.70. ______ Many of these fears spring from ignorance. And although it is hard to separate the paranoia from the benefits, the fact remains that genetic engineering offers ways of solving serious medical and agricultural problems. A. Western farmers have already bred cattle with mare muscle than a skeleton can carry. B. Supporters say the tomato, unsurprisingly called Flaw Saw, will taste better because it will be able to mature on the branch longer. C. Consumer opposition means that there are genetically manipulated foods on the German markets, and the Norwegian government has recently put research into genetically engineered foods on hold. D. For example, if a corn gene is introduced into a wheat gene for pest resistance, will those who are allergic to corn then be allergic to wheat? E. "Mushrooms in the past were almost impossible to cross," says Philippe Callac, one of the three scientists working on the mushroom. F. Genetic engineering will interfere with the balance of nature.

填空题 Read the following text and fill each of the numbered spaces with ONE suitable word. Write your answers on ANSWER SHEET 1. You may say that the business of marking books is going to slow down your reading. {{U}}(31) {{/U}}probably will. That's one of the{{U}} (32) {{/U}}for doing it. Most of us have been taken in by the notion that speed of{{U}} (33) {{/U}}is a measure of our intelligence. There is{{U}} (34) {{/U}}such thing as the right{{U}} (35) {{/U}}for intelligent reading. Some things should be{{U}} (36) {{/U}}quickly and effortlessly, and some should be read{{U}} (37) {{/U}}and even laboriously. The sign of intelligence{{U}} (38) {{/U}}reading is the ability to read{{U}} (39) {{/U}}thing differently according to their worth. In the{{U}} (40) {{/U}}of good books, the point is not to see how many of them you can get through, {{U}}(41) {{/U}}how many cart you get through-bow many you can{{U}} (42) {{/U}}your own. A few friends are{{U}} (43) {{/U}}than a thousand acquaintances. If this be your goal, {{U}}(44) {{/U}}it should be, you will not be impatient if it takes more time and effort to read a great book than it{{U}} (45) {{/U}}a newspaper. You may have another objection to{{U}} (46) {{/U}}books. You can't lend them to your friends{{U}} (47) {{/U}}nobody else can read them{{U}} (48) {{/U}}being distracted by your notes. What's more, you won't want to lend them because a{{U}} (49) {{/U}}copy is a kind of intellectual diary, and{{U}} (50) {{/U}}it is almost like giving your mind away. If your friend hopes to read your "Shakespeare", or "The Federalist Papers", tell him, gently but firmly, to buy a copy. You will lend him your car or your coat-but your books are as much a part of you as your head or your heart.

填空题 As the Internet has rapidly become a mainstream medium, the social impact of the Internet has been a topic of ongoing debate. Some studies have found that Internet use is associated with reduced social networks and increased loneliness. Internet use appears to cause a decline in psychological well-being, {{U}}(31) {{/U}} to research at Carnegie Mellon University. Even people {{U}}(32) {{/U}} spent just a few hours a week {{U}}(33) {{/U}} the Internet experienced more depression and loneliness {{U}}(34) {{/U}} those who logged on less frequently, the two-year study showed. And it wasn't {{U}}(35) {{/U}} people who were already feeling had spent more time on the internet, {{U}}(36) {{/U}} that using the Net actually appeared to {{U}}(37) {{/U}} the bad feelings. Researchers are puzzling over the results, {{U}}(38) {{/U}} were completely contrary {{U}}(39) {{/U}} their expectation. They expected that the Net would {{U}}(40) {{/U}} socially healthier than television, since the Net allows {{U}}(41) {{/U}} to choose their information and to communicate {{U}}(42) {{/U}} others. The fact {{U}}(43) {{/U}} Internet use reduces time available for family and friends may account {{U}}(44) {{/U}} the drop in well-being, researchers hypothesized. Faceless, bodiless "virtual" communication may be less psychologically satisfying than {{U}}(45) {{/U}} conversation, and the relationships formed through it may be shallower. {{U}}(46) {{/U}} possibility is that exposure {{U}}(47) {{/U}} the wider world via the Net makes users less {{U}}(48) {{/U}} with their lives. "But it's important to remember this is {{U}}(49) {{/U}} about the technology, per se; it's about {{U}}(50) {{/U}} it is used," says psychologist Christine Riley of Intel, one of the study's sponsors. "It really points to the need for considering social factors in terms of how you design applications and services for technology."

填空题 {{B}}Which book...{{/B}} {{B}}A{{/B}} Change can be a blessing or a cruse, depending on your perspective. The message of Who Moved My Cheese? is that all can come to see it as a blessing, if they understand the nature of cheese and the role it plays in their lives. Who Moved My Cheese? is a parable that takes place in a maze. Four beings live in that maze: Sniff and Scurry are mice—nonanalytical and nonjudgmental, they just want cheese and are willing to do whatever it takes to get it. Hem and Haw are "little people", mouse-size humans who have an entirely different relationship with cheese. It's not just sustenance to them; it's their self-image. Their lives and belief systems are built around the cheese they've found. Most of us reading the story will see the cheese as something related to our livelihoods—our jobs, our career paths, the industries we work in—although it can stand for anything, from health to relationships. The point of the story is that we have to be alert to changes in the cheese, and be prepared to go running off in search of new sources of cheese when the cheese we have runs out. Dr. Johnson, co-author of The One Minute Manager and many other books, presents this parable to business, church groups, schools, military orgazinations—any place where you find people who may be nervous about or resist change. And although more analytical and skeptical readers may find the tale a little too simplistic, its beauty is that it sums up all natural history in just 94 pages: Thingy change. They always have changed and always will change. And while there's no single way to deal with change, the consequence of pretending change won't happen is always the same: The cheese runs out.{{B}}B{{/B}} Personal-finance author and lecturer Robert Kiyosaki established his unique economic perspective through exposure to a pair of disparate influences: his own highly educated but fiscally unstable father, and the multimillionaire eighth-grade dropout father of his clout friend. The lifelong monetary problems experienced by his "poor dad" (whose weekly paychecks, while respectable, were never quite sufficient to meet family needs) pounded home the counterpoint communicated by his "rich dad" (that "the poor and the middle class work for money", but "the rich have money work for them"). Taking that message to heart, Kiyosaki was able to retire at 47. Rich Dad, Poor Dad, written with consultant and CPA Sharon L. Lechter, lays out the philosophy behind his relationship with money. Although Kiyosaki can take a frustratingly long time to make his points, his book nonetheless compellingly advocates for the type of "financial literacy" that's never taught in schools. Based on the principle that income-generating assets always provide healthier bottom-line results than even the best of traditional jobs, it explains how these assets might be acquired so that the jobs can eventually be shed.{{B}}C{{/B}} What do you do after you've written the No.1 best-seller The Millionaire Next Door? Survey 1, 371 more millionaires and write The Millionaire Mind. Dr. Stanley's extremely timely tone is a mixture of entertaining elements. It resembles Regis Philbin's hit show (and CD-ROM game) Who Wants to Be a Millionaire, only you have to pose real-life questions, instead of quizzing about trivia. Are you gambling, divorce-prone, conspicuously consuming "Income-Statement Affluent" Jacuzzi fool soon to be parted from his or her money, or a frugal, Noyal, resole your shoes and buy your own groceries type like one of Stanley's "Balance-Sheet Affluent" millionaires? "Cheap dates," millionaires are 4.9 times likelier to play with their grandkids than shop at Brooks Brothers. "If you asked the average American what it takes to be a millionaire," he writes, "they'd probably quoted a number of predictable factors: inheritance, luck, stock market investments... Topping his list would be a high IQ, high SAT scores and gradepoint average, along with attendance at a top college." No way, says Stanley, backing it up with data he compiled with help from the University of Georgia and Harvard geodemographer Jon Robbin. Robbin may wish he'd majored in socializing at LSU, instead, because the numbers show the average millionaire had a lowly 2.92 GPA, SAT scores between 1100 and 1190, and teachers who told them they were mediocre students but personable people. "Discipline 101 and Tenacity 102" made them wealthy. Stanley got straight C's in English and writing, but he had money-minded drive. He urges you to pattern your life according to Yale professor Robert Stemberg's Successful Intelligence, because Stanley's statistics bear out Stemberg's theories on what makes minds succeed—and it ain't IQ. Besides offering insights into millionaires' pinchpenny ways, pleasing quips ("big brain, no bucks"), and 46 statistical charts with catchy titles, Stanley's book booms with human-potential pep talk and bristles with anecdotes—for example, about a bus driver who made $ 3 million, a doctor (reporting that his training gave him zero people skills) who lost $ 1.5 million, and a loser scholar in the bottom 10 percent on six GRE tests who grew up to be Martin Luther King Jr. Read it and you'll feel like a million bucks.· places an stress on something that can hardly be learnt at school? 71. ______· is particularly helpful for those who fear changes? 72. ______· tells readers it doesn't follow that those who don't have good academic achievement will not make a fortune? 73. ______· is not written by a single writer? 74. ______· tells a very simple story but it contains many messages? 75. ______· seems not to express ideas straightforward? 76. ______· is written by the one who also wrote a lot of other works with other writers? 77. ______· is probably full of facts? 78. ______· is not only statistical but also interesting? 79. ______· is not related to finance? 80. ______

填空题is now considered the center of industry, transportation, commerce and finance in the mid-west area.

填空题·was especially worshiped by teenagers?

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填空题 Pollution is a "dirty" word. To pollute means to contaminate--to spoil something by introducing impurities which make {{U}}(31) {{/U}} unfit or unclean to use. Pollution comes in many forms. We see it, smell it, {{U}}(32) {{/U}} it, drink it, and stumble through it. We literally lived in and breathe pollution, and {{U}}(33) {{/U}} surprisingly, it is beginning to {{U}}(34) {{/U}} our health, our happiness, and our very civilization. Once we thought of pollution {{U}}(35) {{/U}} meaning simply smog--the choking, stinging, dirty {{U}}(36) {{/U}} that hovers over cities. But air pollution, while it is {{U}}(37) {{/U}} the most dangerous, is only one type of contamination among several {{U}}(38) {{/U}} attack the most basic life functions. Through the uncontrolled use of insecticides, man has polluted the land, {{U}}(39) {{/U}} the wildlife. By {{U}}(40) {{/U}} sewage and chemicals into river and lakes, we have contaminated our {{U}}(41) {{/U}} water. We are polluting the oceans, too, killing the fish and {{U}}(42) {{/U}} depriving ourselves {{U}}(43) {{/U}} an invaluable food supply. Part of the problem is our exploding {{U}}(44) {{/U}}. More and more people produce more wastes. But this problem is intensified by our "throw-away" technology. Each year Americans {{U}}(45) {{/U}} of 7 million autos, 20 million tons of waste paper, 25 million pounds of toothpaste tubes and 48 million cans. We throw away gum wrappers, newspapers, and paper plates. It is no longer fashionable to {{U}}(46) {{/U}} anything. Today almost everything is disposable. {{U}}(47) {{/U}} of repairing a toaster or a radio, it is easier and cheaper to buy a new one and discard the old, even {{U}}(48) {{/U}} 95 percent of its parts may still be functioning. Baby diapers, which used to be made of reusable cloth, are now paper throw-aways. Soon we will wear clothing made of {{U}}(49) {{/U}} :"Wear it once and throw it away, "will be the slogan of the fashion. Where is this all to end? Are we turning the world into a gigantic dump, or is there hope that we can solve the pollution problem? {{U}}(50) {{/U}} solutions are in sight. A few of them are positively ingenious.

填空题WhousuallytakecareoftheelderlypeopleintheUnitedStates?

填空题covers an area of over 69 square miles.

填空题Accordingtothepassage,whatwereparentsusuallyexpectedtoprovidefortheirchildren?

填空题 Read the following text and fill each of the numbered spaces with ONE suitable word. Write your answers on ANSWER SHEET 1. Pollution is a "dirty" word. To pollute means to contaminate--topsoil or something by introducing impurities which make{{U}} (31) {{/U}}unfit or unclean to use. Pollution comes in many forms. We see it, smell it,{{U}} (32) {{/U}}it, drink it, and stumble through it. We literally lived in and breathe pollution, and{{U}} (33) {{/U}}surprisingly,it is beginning to{{U}} (34) {{/U}}our health,our happiness,and our civilization. Once we thought of pollution{{U}} (35) {{/U}}meaning simply the smog—the choking, stinging, dirty{{U}} (36) {{/U}}that hovers over cities. But air pollution, while it is{{U}} (37) {{/U}}the most dangerous, is only one type of contamination among several{{U}} (38) {{/U}}attack the most basic life functions. Through the uncontrolled use of insecticides, man has polluted the land,{{U}} (39) {{/U}}the wildlife. By{{U}} (40) {{/U}}sewage and chemicals into rivers and lakes, we have contaminated our{{U}} (41) {{/U}}water. We are polluting the oceans, too, kilting the fish and{{U}} (42) {{/U}}depriving ourselves{{U}} (43) {{/U}}an invaluable food supply. Part of the problem is our exploding{{U}} (44) {{/U}}. More and more people are producing more wastes. But this problem is intensified by our "throw-away" technology. Each year Americans{{U}} (45) {{/U}}of 7 million autos, 20 million tons of waste paper, 25 million pounds of toothpaste tubes and 48 million cans. We throw away gum wrappers, newspapers, and paper plates. It is no longer wise to{{U}} (46) {{/U}}anything. Today almost everything is disposable.{{U}} (47) {{/U}}of repairing a toaster or a radio, it is easier and cheaper to buy another one and discard the old,even{{U}} (48) {{/U}}95 percent of its parts may still be functioning. Baby diapers,which used to be made of reusable cloth, are now paper throw-aways. Soon we will wear clothing made of{{U}} (49) {{/U}}:" Wear it once and throw it away" will be the slogan of the fashionable consciousness. Where is this all to end? Are we turning the world into a gigantic dump,or is there hope that we can solve the pollution problem?{{U}} (50) {{/U}}, solutions are in sight. A few of them are positively ingenious.

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填空题 You'll hear a talk on Open University. As you listen, you must answer questions 21—30 by writing NO MORE THAN THREE words in the space provided for you, you 7l hear the talk TWICE.

填空题has strengthened links with the Southern part of China?

填空题Psychologists take contrastive views of how external rewards, from 1 praise to cold cash, affect motivation and creativity. Behaviorists, 2 research the relation 3 actions and their consequences argue that rewards can improve performance at work and school. Cognitive researchers, who study various aspects of mental life, maintain 4 rewards often destroy creativity 5 encouraging dependence 6 approval and gifts from others. The latter view has gained many supporters, especially 7 educators. But the careful use of small monetary rewards sparks 8 in grade-school children, suggesting 9 properly presented inducements indeed aid inventiveness, 10 to a study in the June Journal of Personality and Social Psychology. "If kids know they"re working for a 11 and can focus 12 a relatively challenging task, they show the most creativity", says Robert Eisenberger of the University of Delaware in Newark. "But it"s easy to kill creativity by giving rewards for 13 performance or creating too 14 anticipation for re-wards. "A teacher 15 continually draws attention to rewards or who hands 16 high grades for ordinary achievement ends up 17 discouraged students, Eisenherger holds. 18 an example of the latter point, he notes growing efforts at major universities to tighten grading standards and restore failing 19 . In earlier grades, the use of so-called token economies, in 20 students handle challenging problems and receive performance-based points toward valued rewards, shows promise in raising effort and creativity, the Delaware psychologist claims.

填空题Note: When more than one answer is required, these may be given in any order. Some choices may be required more than once. A=Saturn B=Venus C=Mercury Which planets ... · has been explored by 15 spacecraft? 21. ______ · has a system of rings and more than I satellites? 22. ______ · has a weak magnetic field? 23. ______ · has the lowest density? 24. ______ · is named after the Roman goddess of beauty? 25. ______ · was believed to have a sinister influence upon people? 26. ______ · was thought by ancient people as two separate stars? 27. ______ · is completely covered with opaque clouds? 28. ______ · are closer to the Sun than the Earth? 29. ______ 30. ______ Saturn For beauty and interest alike, there are few objects in the starry heavens to compare with Saturn. This magnificent planet, with the system of rings that encircles it, provides an unforgettable spectacle when it is viewed through a powerful telescope. The Saturnian system includes not only the planet and its rings, but also 11 or more satellites, or moons. To the ancients Saturn appeared to be the most insignificant of the heavenly bodies that were supposed to circle the earth (the sun, the moon, Mercury, Venus, Mars, Jupiter, and Saturn), as distinguished from the fixed stars. The glorious rings that surround the planet were invisible before the invention of the telescope in the first decade of the seventeenth century. Otherwise this magnificent crown might have saved Saturn from the sinister reputation that it once bore. Ancient astrologers maintained that it had a sinister influence upon people. Saturn is far from the center of the solar system. The mean distance of Saturn from the sun is 1,428,000,000 kilometers, or about 9.5 times the distance of the earth from the sun. The density of Saturn is very low, much lower than that of any other planet. In fact it is only about three-quarters that of water. Because of this fact some astronomers hold that Saturn is far from having reached the solid condition. Venus The beautiful white planet whose orbit lies between those of Mercury and of the Earth is called Venus after the Roman goddess of beauty. The planet is similar to our earth in size and mass. Its diameter is about 12,100 kilometers; the earth's is 12,725 kilometers. Its mass is a little more than four-fifths that of the earth. Its density is about nine-tenths that of our planet. Venus revolves around the sun once every 225 days in an orbit that is very nearly circular. As the planet revolves, it rotates about its axis once every 243.1 earth days, from east to west instead of in the west-to-east direction of most other celestial bodies. The planet is tilted only slightly with respect to the plane of its orbit. As it proceeds along its orbit, Venus is sometimes on the far side of the sun from the earth, or at superior conjunction. At other times Venus is between the sun and the earth, at inferior conjunction. At superior conjunction it is quite far form earth. But at inferior conjunction it is only about 41,840,000 kilometers away -closer than any other planet. These variations in distance result in notable differences in the apparent size of the planet as viewed from the earth, at inferior conjunction, the apparent diameter is six times greater than at superior conjunction. Venus has been explored by 15 spacecraft of which five were from the United States and ten were from the soviet Union. Some of these were orbiters, some were landers, and some were both. The planet is completely covered with opaque clouds, which make an almost perfect reflecting layer. Mercury Mercury is the nearest of the planets to the sun. It is the smallest of all and also, at certain intervals, one of the brightest. In spite of that fact, it is generally not easy to see with the naked eye. For one thing, it appears in the heavens only during the hours of twilight and dawn, when even very bright stars do not appear at their best. Besides, it is often obscured by haze near the horizon. The great Polish astronomer Nicholas Copernicus once lamented the fact that he had not been able to see Mercury at all in his many years of observation of the heavens. Perhaps this was due to the nature of the district where he lived -the low and misty region of eastern Prussia where the Vistula flows into the Baltic. Mercury makes such a small circuit around the sun that it is always comparatively near that body. It never rises in the morning or sets in the evening much before or after the sun. Because of its appearance sometimes in the east and sometimes in the west, some ancient peoples including the Egyptians, Hindus, and Greeks, thought of it as two separate heavenly bodies -a morning star and an evening star. The Greeks called the morning star "Apollon" after the god of the sun, and the evening star "Hermes," the name of the swift messenger of the gods, because the planet's apparent motion among the stars was so swift. It is said that the Greek philosopher Pythagoras, who lived in the sixth century B.C., was the first to recognize that the morning star and evening star were one and the same heavenly body. That fact was well known to Roman astronomers. Hermes was worshiped by the Romans under the name of Mercury. Scientists were surprised to discover that Mercury has a very thin atmosphere consisting of helium. It is so thin that the word "atmosphere" gives the wrong impression, but no such gas envelope has been expected at all. Another surprise was that Mercury has a weak magnetic field. Whether this field is produced by the planet itself or produced in some way by the solar wind -the stream of particles flowing out from the sun -is not yet certain. But at any rate, the interior of Mercury is probably earthlike in composition, with an iron core and a less dense outer crust.

填空题Wherewastheletterprobablyplacedmanyyearsago?

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