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Passage Five When you watch a football game on a Saturday afternoon, you feel secure in your knowledge of what will happen when a player boots the ball. It first goes up and then it comes down. That’s how it is, was, and will be--unless.... if the kicker someday should kick the ball such that at the instant it left his toe it were travelling upward at a rate of 11.2 kilometers per second (25 000 mhr). We would find that we would not have to worry about a punt return, because the ball simply would not come down. This particular speed is the escape velocity of an object from the earth. At this speed, any object, large or small, will escape from the earth to soar forever upward until captured by the gravitational attraction of some other planet or heavenly body. At first thought it might seem that a heavy object might require a greater initial speed to escape from the surface of the earth than a lighter one, remember that the way objects fall (or move upward against gravity) is independent of the mass of the object. As a result, if a velocity of 11.2 kilometers per second is enough to cause a football to escape from the earth, it is also enough to send a bowling ball (or a freight car) on its way. The concept of escape velocity applies to objects as small as atoms and molecules. The earth’s atmosphere is composed primarily of oxygen and nitrogen, and it contains practically no trace of hydrogen or helium, the lightest elements. All the atoms of a gas travel in random motion at very high speeds, and the less massive atoms and molecules travel at the greatest speeds. In fact, the lighter gases go so fast that their speeds are greater than the critical speed of 11.2 kilometers per second. Thus they have long ago left our comfortable home and are now wandering through space in search of a more hospitable gravitational field. The moon has a weaker gravitation field than the earth. The escape velocity of an object on the moon is about 2.4 kilometers per second, and even the heavier gases have enough speed to escape the moon. This explains why we find no atmosphere there; any gases that may be released near the moon quickly escape. Helium is not found in the earth’s atmosphere because ______.
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第三篇 Inspecting a Used Car The scariest part of buying a used car is not being completely sure of what condition it’s in. A car that’s been in a major accident is always a bigger risk, but sellers often try to hide this information. Andrew Blealdey, evaluator-inspector, runs a mobile vehicle inspection service in Montreal. For about $ 80 be will perform a full, unbiased inspection on a used vehicle. In his 10 years as a professional inspector, Bleakley has seen a lot. He warns "Watch out for dealer demonstration vehicles which are used not new. They may have been in a collision." He adds that it is not uncommon in Ontario and Quebec especially for unscrupulous sellers to roll back the odometer or to even disengage it. Bleakiey has special tools to check for this. Bleakley always recommends hiring all independent technician to inspect the condition of a used car before you buy it. The problem is finding someone qualified to do the inspection. Which he says generally doesn’t mean just any mechanic. A thorough mechanical inspection includes checking the compression, all major systems, including the engine, electrical and charging systems, transmission and drive line, fluids, brakes, suspension, and steering. Essential, too, is all inspection of the car’s body and finally a road test. There are, however, a few things everyone can do before buying a used Car: Do a visual check of the car. Look at the right rear door hinges. If they are very worn, or the door doesn’t close well, the car may have been used as a taxi. Holes in the roof could mean the car was used for deliveries. Check for oil leaks on the pavement. Note that leaks are not necessarily a significant problem-- it depends on the cause. Don’t assume that new 100 king brake and accelerator pedals mean the car hash’t been driven much. Resellers know people check these details and can buy new pads for around $ 6. Copy down the vehicle identification number (VIN), a 17-character combination of numbers and letters, from the vehicle’s dashboard. In Ontado, ask the dealer or seller for the Used Vehicle Information Package. This gives details of previous owners, any outstanding liens on the car, and thefair market value of the vehicle. collision n.碰撞；碰撞事故 odometer n.里程表 compression n.压缩；压缩量 brake n．刹车 pedal n．踏脚 lien n，扣押权 unscrupulous adj.办不择手段的 disengage v.松开；使脱离 transmission n．传输 suspension n，悬架 hinge n，铰链 dashboard n．仪表板 According to the passage, from which of the following can the buyer obtain reliable information of the previous owner
阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从4个选项中选择1个最佳答案，并填在题前的括号内。 A Health Profile A health profile is a portrait of all of the factors that influence your health. To draw your health profile, you will (1) what diseases run in your family, what health hazards you may be exposed to (2) work, how your daily (3) compares to the recommended standards, how much time per week you (4) exercising and what type of exercise you engage (5) , how stressful your work and family environments are, what kinds of illnesses you get regularly, and (6) or not you have any one of a number of addictions. (7) this portrait, your should have a checkup to determine how your blood, heart, and lungs are functioning. This checkup will serve (8) a baseline, to which you can then compare later tests. (9) this profile is thoroughly drawn, you can begin to think about setting health priorities based (10) your particular portrait. For example, if you drink two martinisevery evening, have a high-stress (11) , are overweight, smoke a pack of cigarettes a day, and use marijuana occasionally on weekends, you should quit smoking first, followed (12) losing the excess weight, reducing the stress of your job, giving up your marihuana habit, and then finally giving some (13) to those martinis if you want to prevent first cancer, and then heart disease. Even for the youthful working person who has never been sick a day in his life, who is (14) excellent health, a good look at all health habits and at work and home environments may suggest changes that .will (15) him in the future. profile n. 侧影,概貌 hazard n, 危险,危害 checkup n. 健康检查,体检 martini n. 马提尼洒 portrait n. 画像,肖像 addiction n. 嗜好, baseline n. 基础,起点 marihuana n. 大麻烟(一种毒品)
第二篇 Some Things We Know about Language Many things about language are a mystery, and many will always remain so. But some thingswe do know. First, we know that all human beings have a language of some sort. There is no race of men anywhere on earth so backward that it has no language, no set of speech sounds by which the people communicate with one another. Furthermore, in historical times, there has never been a race of men without a language. Second, there is no such thing as a primitive language. There are many people whose cultures are undeveloped, who are, as we say, uncivilized, but the languages they speak are not primitive. In all known languages we can see complexities that must have been tens of thousands of years in developing. This has not always been well understood; indeed, the direct contrary has often been stated. Popular ideas of the language of the American Indians will illustrate. Many people have supposed that the Indians communicated in a very primitive system of noises. Study has proved this to be nonsense. There are, or were, hundreds of American Indian languages, and all of them turn out to be very complicated and very old. They are certainly different from the languages that most of us are familiar with, but they are no more primitive than English and Greek. A third thing we know about language is that all languages are perfectly adequate. That is, each one is a perfect means of expressing the culture of the people who speak the language. Finally, we know that language changes. It is natural and normal for language to change; the only languages which do not change are the dead ones. This is easy to understand if we look backward in time. Change goes on in all aspects of language. Grammatical features change as do speech sounds, and changes in vocabulary are sometimes very extensive and may occur very rapidly. Vocabulary is the least stable part of any language. According to the author language changes are most likely to occur in ______.
阅读下面这篇短文，短文后有2项测试任务：(1)l～4题要求从所给的6个选项中为第 2～5段每段选择1个正确的小标题；(2)第5～8题要求从所给的6个选项中选择4个正确的选项，分别完成每个句子。请将答案写在相应的横线内。 The Fridge The fridge is considered a necessity. It has been so since the 1960s when packaged food first appeared with the label: "store in the refrigerator." In my fridgeless Fifties childhood, I was fed well and healthily. The milkman came daily, the grocer, the butcher, the baker, and the ice-cream man delivered two or three times a week. The Sunday meat would last until Wednesday and surplus bread and milk became all kinds of cakes. Nothing was wasted and we were never troubled by rotten food. Thirty years on, food deliveries have ceased, fresh vegetables are almost unobtainable in the country. The invention of the fridge contributed comparatively little to the art of food preservation. A vast variety of well-tried techniques already existed--natural cooling, drying, smoking, slating, sugaring, bottling... What refrigeration did promote was marketing--marketing hardware and electricity, marketing soft drinks, marketing dead bodies of animals around the globe in search of a good price. Consequently, most of the world’s fridges are to be found, not in the tropics where they might prove useful, but in the wealthy countries with mild temperatures where they are climatically almost unnecessary. Every winter, millions of f-ridges hum away continuously, and at vast expanse, busily maintaining an artificially-cooled space inside an artificially-heated house--while outside, nature provides the desired temperature free of charge. The fridge’s effect upon the environment has been evident, while its contribution to human happiness has been insignificant. If you don’t believe me, try it yourself. Invest in a food cabinet and turn off your fridge next winter. You may miss the hamburgers but at least you’ll get ride of that terrible hum. If you stop using the fridge, at least you won’t be troubled by the noise______
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