2020年6月大学英语六级阅读晨读美文：Marine Mammals_128
2020年6月大学英语六级长篇阅读练习题（三篇）
【导语】锲⽽舍之，朽⽊不折；锲⽽不舍，⾦⽯可镂。
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If a freed atom collides with an oxygen molecule, it becomes ozone. Stratospheric ozone has been called “good” ozone because it protects the Earth’s surface from dangerous ultraviolet light. C) Ozone can also be found in the troposphere, the lowest layer of the atmosphere. Tropospheric ozone (often termed “bad ” ozone) is man - made, a result of air pollution from internal combustion engines and power plants. Automobile exhaust and industrial emissions release a family of nitrogen oxide gases (NOx) and volatile organic compounds (VOC), by-products of burning gasoline and coal. NOx and VOC combine chemically with oxygen to form ozone during sunny, high- temperature conditions of late spring, summer and early fall. High levels of ozone are usually formed in the heat of the afternoon and early evening, dissipating during the cooler nights. D) Although ozone pollution is formed mainly in urban and suburban areas, it ends up in rural areas as well, carried by prevailing winds or resulting from cars and trucks that travel into rural areas. Significant levels of ozone pollution can be detected in rural areas as far as 250 miles downwind from urban industrial zones. E) You can make ozone test strips to detect and monitor ozone levels in your own backyard or around your school. You will need corn starch, filter paper (coffee filters work well) and potassium iodide (can be ordered from a science education supplier such as Carolina Biological Supply or Fisher Scientific). Basically, you make a paste from water, corn starch and potassium-iodide, and you paint this paste on strips of filter paper. You then expose the strips to the air for eight hours. Ozone in the air will react with the potassium iodide to change the color of the strip. You will also need to know the relative humidity, which you can get from a newspaper, weather broadcast or home weather station. F) When you inhale ozone, it travels throughout your respiratory tract. Because ozone is very corrosive, it damages the bronchioles and alveoli in your lungs, air sacs that are important for gas exchange. Repeated exposure to ozone can inflame lung tissues and cause respiratory infections. G) Ozone exposure can aggravate existing respiratory conditions such as asthma, reduce your lung function and capacity for exercise and cause chest pains and coughing. Young children, adults who are active outdoors and people with respiratory diseases are most susceptible to the high levels of ozone encountered during the summer. In addition to effects on humans, the corrosive nature of ozone can damage plants and trees. High levels of ozone can destroy agricultural crops and forest vegetation. H) To protect yourself from ozone exposure, you should be aware of the Air Quality Index (AQI) in your area every day—you can usually find it in the newspaper or on a morning weather forecast on TV or radio. You should also be familiar with the U.S. Environmental Protection Agency (EPA) guide for ozone-alert values. I) What do the numbers in the AQI mean? The AQI measures concentrations of five air pollutants: ozone, sulfur dioxide, particulate matter, carbon monoxide and nitrogen dioxide. The EPA has chosen these pollutants as criteria pollutants, but these are not all of the pollutants in the air. These concentrations are compared to a standard set out in federal law. An index value of 100 means that all of the criteria pollutants are at the maximum level that is considered safe for the majority of the population. To reduce your exposure to ozone, you should avoid exercising during afternoon and early evening hours in the summer. J) There are several ways you can help to decrease ozone pollution. Limit using your automobile during afternoon and early evening hours in the late spring, summer and early fall. Do not use gasoline-powered lawn equipment during these times. Do not fuel your car during these times. Do not light fires or outdoor grills during these times. Keep the engine of your car or boat tuned. Make sure that your tires are properly inflated. Use environmentally safe paints, cleaning and office products (some of these chemicals are sources of VOC). K) Besides personal attempts to reduce ozone pollution, the EPA has initiated more stringent air-quality standards (such as the Clean Air Act and its modifications) to reduce air pollution. Compliance with these standards by industries, manufacturers and state and local governments has significantly reduced the levels of many common air pollutants. L) With continued conservation and reduction practices, adherence to ozone-pollution warnings, research and government regulation, ozone-pollution levels should continue to fall. Perhaps future generations will not be threatened by this environmental pollutant. M) The thing that determines whether ozone is good or bad is its location. Ozone is good，when it is in the stratosphere. The stratosphere is a layer of the atmosphere starting at the level of about 6 miles (about 10 kilometers) above sea level. The stratosphere naturally contains about six parts per million of ozone, and this ozone is very beneficial because it absorbs UV radiation and prevents it from reaching us. N) Ozone is “bad” when it is at ground level. Ozone is a very reactive gas that is hard on lung tissue. It also damages plants and buildings. Any ozone at ground level is a problem. Unfortunately, chemicals in car exhaust and chemicals produced by some industries react with light to produce lots of ozone at ground level. In cities, the ozone level can rise to a point where it becomes hazardous to our health. That’s when you hear about an ozone warning on the news. 1. When ultraviolet rays from the sun separate an oxygen molecule into two single oxygen atoms in the stratosphere, the combination of a single oxygen atom and an oxygen molec u l e f o r m s o z o n e . / p > p b d s f i d = " 1 2 6 " > 0 0 2 . Y o u ca n m a k e o z o n e t e s t s t r i p sb y y o u r s e l f t o f i n d o u t a b o u t o z o n e l e v e l s i n y o u r o w n l oc a l e . / p > pb d s f i d = " 1 2 7 " > 0 0 3 . L o n g - t i m e e x p o s u r e t o o z o n e i s b a d l y h a r m f u l t o o u r r e s p i r a t o r y s y s t e m . / p > p b d s f i d = " 1 2 8 " > 0 0 4 . C h e m ic a l s i n i nd u s t r i a l w a s te g a s a n d v e h i c l e e x h a u s t r e a c t w i t h l i g h t t of o r m l o t s o f o z o n e a tg r o u n d l e v e l . / p > p b d s f i d = " 1 2 9 " > 0 0 5 . I n t e r n a l c o m b u s t i o n e n g i n e s a n d p o w e r p l a n t s c a u s e th e a r ti f i c i a l t r o p o s p h e r i c o z o n e , a l s o k n o w n a s b a d o z o n e . / p > p b d s f i d = " 1 3 0 " > 0 0 6 . O z o n e i s v e r y h e l p f u l b e c a u s e i t a b s o r b s U V r a d i a t i o n a n d s e p a r a t e s u s f r o m i t . / p > p b d s f i d = " 1 3 1 " > 0 0 7 . U s i n g g a s o l i n e - p o w e r e d l a w n e q u i p m e n t i n t h e l a t e s p r i n g , s u m m e r a n d e a r l y f a l l m a y i n c r e a s e o z o n e p o l l u t i o n . / p > p b d s f i d = " 1 3 2 " > 0 0 8 . O z o n e p o l l u t i o n o c c u r s i n u r b a n a n d s u b u r b a n a r e a s a s w e l l a s i n r u r a l a r e a s . / p > p b d s f i d = " 1 3 3 " > 0 0 9 . I n o r d e r t o d e c r e a s e o z o n e p o l l u t i o n , t h e E P A h a s s e t u p m o r e r i g o r o u s a i r - q u a l i t y s t a n d a r d s . / p > p b d s f i d = " 1 3 4 " > 0 0 1 0 . P a y c l o s e a t t e n t i o n t o t h e A i r Q u a l i t y I n d e x i n y o u r a r e a e v e r y d a y c a n k e e p y o u a w a y f r o m o z o n e e x p o s u r e . / p >。
2020年6月大学英语六级长篇阅读练习题
2020年6月大学英语六级长篇阅读练习题（1）10 Ways Obama Could Fight Climate Change[A] One of the biggest surprises of President Barack Obama's inaugural address,on Monday was how much he focused on fighting climate change, spending more time on that issue than any other. "We will respond to the threat of climate change, knowing that the failure to do so would betray our children and future generations," Obama said. The President pointed out that recent severe weather supplied an urgent impetus for energy innovation and staked the nation's economic future on responding to a changing climate. "We cannot cede to other nations the technology that will power new jobs and new industries--we must claim its promise," Obama said. '" That's how we will maintain our economic vitality and our national treasure--our forests and waterways; our croplands and snowcapped (山顶积雪的) peaks. That is how we will preserve our planet, commanded to our care by God. " so what could the President reasonably do to deliver on that vow? Here are ten of their suggestions:Sunset coal with new incentives and regulations.[B] "Provide incentives to phase out the oldest, most polluting power plants," said Robert Jackson, a climate scientist at Duke University. It's already happening, to some degree, as more of the nation transitions to natural gas. Earth scientist Bill Chameides, dean of Duke's Nicholas School of the Environment and a former chief scientist at the Environmental Defense Fund, urges the administration to use its Clean, Air Act authority to promulgate (颁布)carbon regulations for existing power plants like it has for new ones: "Doing that will force fuel switching from coal to natural gas. "Invest federal stimulus money in nuclear power.[C] It's hardly a perfect fuel, as accidents like Japan's Fukushima fallout have shown, but with safety precautions new nuclear plants can meaningfully offset dirtier types of energy, supporters say."Nuclear is the only short-to medium-term way to really get away from fossil fuels," said Peter Raven. President emeritus of the Missouri Botanical Garden. He said the damage done by relentless global warming will far exceed the damage done by faults in the nuclear system.Kill the Keystone pipeline.[D] The controversial Keystone XL oil pipeline is up for review again by the White House this year. "The font thing he should do to set the tone to a lowercarbon economy is to reject the Keystone pipeline, “said Raymond Pierrehum Bert, a geophysical scientist at the University of Chicago. The pipeline was never going to be a major driver of global emissions, but Pierre humbert and some other environmentalists say that by killing it the President would send a clear message about America's intent to ramp down fossil fuels.Protect the oceans by executive order.[E] Land use is complicated, but large swaths of oceans can be protected by executive order. Just as President George W. Bush designated the world's largest marine monument northwest of Hawaii in 2006. Obama could single-handedly protect other areas. National Geographic Explorer-in-Residence Sylvia Earle said the President should focus on parts of the Arctic that are under U. S. control, putting them off limits to energy production, commercial fishing, and mineral exploration. Marine sanctuaries (禁捕区) won't stop climate change, but they can give marine species a better chance of adapting to it by reducing the other man-made threats the animals face.Experiment with capturing carbon.[F] Huge untapped reserves of natural gas and oil make it unlikely that the U. S. will transition away from fossil fuels in the immediate future. Instead, said Wallace Broecker, geology professor at Columbia University's Lamont-Doherty Earth Observatory, we should attack the atmosphere's carbon surplus directly. "Obama could make available funds to build and test prototype air capture units" to capture and store CO2, said Broecker. Removing some carbon from the atmosphere could buy valuable time as policy makers and scientists explore more permanent solutions.Grow government research for new energy sources.[G] The Department of Energy has a nimble program that's tasked with innovative energy research—the Advanced Research Projects Agency-Energy. The ARPA-E funds research in biofuels, transmission,and battery storage, with an annual budget of $ 275 million. Last year, DOE officials requested at least $ 75 million more. Increasing funding for ARPA-E, said Rare Pomerance, former deputy assistant secretary of state for environment and development and currently an environmental consultant, "you get new technologies that undercut coal, oil, and gas. " Plus, he said, yon get a competitive advantage if American researchersuncover the next big idea in new energy.Tax carbon.[H] Congress would have to agree, but many climate experts say that the most meaningful way to tackle emissions is to set a price on carbon. "We should be asking people to pay the cost of putting carbon into the atmosphere as they buy the fuel," said Josh Willis, climate scientist and oceanographer at NASA's Jet Propulsion Laboratory. To gain political support for the idea, Obama would probably have to show that the tax wonld help accelerate technology, grow new industries, and pay down the deficit.Dial back the federal government's energy use.[I] With more than I. 8 million employees, $ 500 billion in annual purchasing power, and 500,000 buildings to operate, the federal government has been a leader in reducing energy use since Obama signed a 2009 executive order to cut waste. "I would urge him to keep using the power of government to promote energy conservation," said Syndonia Bret-Harte, an Arctic biologist who studies climate change at the University of Alaska, Fairbanks.Build a scientific clearinghouse for climate information.[J] "I advocate for building a better information system on what is happening and why," said Kevin Tren berth, head of the Climate Analysis Section at the U. S. National Center for Atmospheric Research. That involves compiling observations related to climate change from around the world and using the data to refine climate modeling. Think of it as a one-stop, user-friendly website that clearly demonstrates how weather data from around the globe are influenced by broader shifts in the planet's climate.Keep talking. Despite a consensus among top scientists, the world still needs some convincing on climate change.[K] A CNN poll last week found that just 49 percent of Americans agree that global warming is real and is due to human activities. "The most important thing the President can do is to build on his inaugural comments to heighten the sense of urgency about rapid climate destabilization and clarify its connection to virtually every other issue on the national agenda," said David Orr, environmental studies professor at Oberlin College. That means using the bully clergymen to show how a more volatile climate affects everything from agriculture totransportation to 21st-century warfare.46. The urge to promulgate carbon regulations is aimed at pushing power plants to replace coal by natural gas.47. Marine sanctuaries should be preserved because they help sea species adapt to climate alteration.48. The government should take the responsibility to raise Americans' awareness about climate change.49. Many climate experts believe that the most effective way to lower emission is to tax on carbon.50. Nuclear supporters argue that nuclear system failures are less challenging than global warming.51. Recent extreme weather made President Obama feel it is urgent to address climate change.52. Keystone pipeline should be rejected because it is a signal to reduce fossil fuels.53. Since Obama signed a 2009 executive order to cut waste, the federal government has taken the lead in saving energy.54. Lower carbon emission will be most likely to happen if research in new energy resources succeeds.55. Compared with turning to new energy, America prefers carbon capture and store as a temporary measure.2020年6月大学英语六级长篇阅读练习题（2）How to Make Attractive and Effective PowerPoint PresentationsA) Microsoft PowerPoint has dramatically changed the way in which academic and business presentations are made. This article outlines few tips on making more effective and attractive PowerPoint presentations.The TextB) Keep the wording clear and simple. Use active, visual language. Cut unnecessary words—a good rule of thumb is to cut paragraphs down to sentences, sentences into phrases, and phrases into key words.Limit the number of words and lines per slide. Try the Rule of Five-five words per line, five lines per slide. If too much text appears on one slide, use the AutoFit feature to split it between two slides. Click within the placeholder to display the AutoFit Options button (its symbol is two horizontal lines with arrows above and below), then click on the button and choose Split Text between Two Slides from the submenu.C) Font size for titles should be at least 36 to 40, while the text body should not be smaller than e only two font styles per slide—one for the title and the other for the text. Choose two fonts that visually contrast with each other. Garamond Medium Condensed and Impact are good for titles, while Garamond or Tempus Sans can be used for the text body.D) Embed the fonts in your presentation, if you are not sure whether the fonts used in the presentation are present in the computer that will be used for the presentation. To embed the fonts: (1) On the File menu, click Save As. (2) On the toolbar, click Tools, click Save Options, select the Embed TrueType Fonts check box, and then select Embed characters in use only.E) Use colors sparingly; two to three at most. You may use one color for all the titles and another for the text body. Be consistent from slide to slide. Choose a font color that contrasts well with the background.F) Capitalizing the first letter of each word is good for the title of slides and suggests a more formal situation than having just the first letter of the first word capitalized. In bullet point lines, capitalize the first word and no other words unless they normally appear capped. Upper and lower case lettering is more readable than all capital letters. Moreover, current styles indicate that using allcapital letters means you are shouting. If you have text that is in the wrong case, select the text, and then click Shift+F3 until it changes to the case style that you like. Clicking Shift+F3 toggles the text case between ALL CAPS, lower case, and Initial Capital styles.G) Use bold or italic typeface for emphasis. Avoid underlining, it clutters up the presentation.Don’t center bulleted lists or text. It is confusing to read. Left align unless you have a good reason not to. Run “spell check” on your show when finished.The BackgroundH) Keep the background consistent. Simple, light textured backgrounds work well. Complicated textures make the content hard to read. If you are planning to use many clips in your slides, select a white background. If the venue of your presentation is not adequately light-proof, select a dark-colored background and use any light color for text. Minimize the use of “bells and whistles” such as sound effects, “flying words” and multiple transitions. Don’t use red in any fonts or backgrounds. It is an emotionally overwhelming color that is difficult to see and read.The ClipsI) Animations are best used subtly; too much flash and motion can distract and annoy viewers. Do not rely too heavily on those images that were originally loaded on your computer with the rest of Office. You can easily find appropriate clips on any topic through Google Images. While searching for images, do not use long search phrases as is usually done while searching the web-use specific words.J) When importing pictures, make sure that they are smaller than two megabytes and are in a .jpg format. Larger files can slow down your show. Keep graphs, charts and diagrams simple, if possible. Use bar graphs and pie charts instead of tables of data. The audience can then immediately pick up the relationships.The PresentationK) If you want your presentation to directly open in the slide show view, save it as a slide show file using the following steps. Open the presentation you want to save as a slide show. On the File menu, click Save As. In the Save astype list, click PowerPoint Show. Your slide show file will be saved with a ppt file extension. When you double-click on this file, it will automatically start your presentation in slide show view. When you’re done, PowerPoint automatically closes and you return to the desktop. If you want to edit the slide show file, you can always open it from PowerPoint by clicking Open on the File menu.L) Look at the audience, not at the slides, whenever possible. If using a laser pointer, don’t move it too fast. For examp le, if circling a number on the slide, do it slowly. Never point the laser at the audience. Black out the screen (use “B” on the keyboard) after the point has been made, to put the focus on you. Press the key again to continue your presentation.M) You can use the shortcut command [Ctrl]P to access the Pen tool during a slide show. Click with your mouse and drag to use the Pen tool to draw during your slide show. To erase everything you’ve drawn, press the E key. To turn off the Pen tool, press [Esc] once.MiscellaneousN) Master Slide Set-Up: The “master slide” will allow you to make changes that are reflected on every slide in your presentation. You can change fonts, colors, backgrounds, headers, and footers at the “master slide” level. First, go to the “View” menu. Pull down the “Master” menu. Select the “slide master” menu. You may now make changes at this level that meet your presentation needs.1. The ways in which academic and business presentations are made have been changed by Microsoft PowerPoint.2. When making the PowerPoint, the wording of the text should not be complicated.3. In each slide, the font styles for the title and the text should contrast with each other.4. A more formal situation is capitalizing the first letter of the first word.5. Centering bulleted lists or text can not help to read.6. Sound effects should be used as less frequently as possible.7. When importing pictures, make sure that they are smaller than two megabytes.8. When making the presentation, you should look at the audience as possible as you can.9. Pressing the E key can help you to erase everything you've drawn.10. In order to meet your presentation needs, you can make changes at the “slide master”level.2020年6月大学英语六级长篇阅读练习题（3）Paper--More than Meets the EyeA) We are surrounded by so much paper and card that it is easy to forget just how complex it is. There are many varieties and grades of paper materials, and whilst it is fairly easy to spot the varieties, it is far more difficult to spot the grades.B) It needs to be understood that most paper and card is manufactured for a specific purpose, so that whilst the corn-flake packet may look smart, it is clearly not something destined for the archives. It is made to look good, but only needs a limited life span. It is also much cheaper to manufacture than high grade card.C) Paper can be made from an almost endless variety of cellulose-based material which will include many woods, cottons and grasses or which papyrus is an example and from where we get the word "paper". Many of these are very specialized, but the preponderance of paper making has been from soft wood and cotton or rags, with the bulk being wood-based.Paper from WoodD) In order to make wood into paper it needs to be broken down into fine strands. Firstly by powerful machinery and then boiled with strong alkalies such as caustic soda, until a fine pulp of cellulose fibers is produced. It is from this pulp that the final product is made, relying on the bonding together of the cellulose into layers. That, in a very small nutshell, is the essence of paper making from wood. However, the reality is rather more complicated. In order to give us our white paper and card, the makers will add bleach and other materials such as china clay and additional chemicals.E) A further problem with wood is that it contains a material that is not cellulose. Something called lignin. This is essential for the tree since it holds the cellulose fibres together, but if it is incorporated into the manufactured paper it presents archivists with a problem. Lignin eventually breaks down and releases acid products into the paper. This will weaken the bond between the cellulose fibers and the paper will become brittle and look rather brown and careworn. We have all seen this in old newspapers and cheap paperback books. It has been estimated that most paper back books will have a life of not greaterthan fifty years. Not what we need for our archives.F) Since the lignin can be removed from the paper pulp during manufacture, the obvious question is "why is it left in the paper?" The answer lies in the fact that lignin makes up a considerable part of the tree. By leaving the lignin in the pulp a papermaker can increase his paper yield from a tree to some 95%. Removing it means a yield of only 35%. It is clearly uneconomic to remove the lignin for many paper and card applications.G) It also means, of course, that lignin-free paper is going to be more expensive, but that is nevertheless what the archivist must look for in his supplies. There is no point whatsoever in carefully placing our valuable artifacts in paper or card that is going to hasten their demise. Acid is particularly harmful to photographic materials, causing them to fade and is some cases simply vanish!H) So, how do we tell a piece of suitable paper or card from one that is unsuitable? You cannot do it by simply looking, and rather disappointingly, you cannot always rely on the label. "Acid-free" might be true inasmuch as a test on the paper may indicate that it is a neutral material at this time. But lignin can take years before it starts the inevitable process of breaking down, and in the right conditions it will speed up enormously.I) Added to this, as I have indicated earlier, paper may also contain other materials added during manufacture such as bleach, china clay, chemical whiteners and size. This looks like a bleak picture, and it would be but for the fact that there are suppliers who will guarantee the material that they sell. If you want to be absolutely sure that you are storing in, or printing on, the correct material then this is probably the only way.J) Incidentally, acids can migrate from material to material. Lining old shoe boxes with good quality acid-free paper will do little to guard the contents. The acid will get there in the end.Paper from RagK) Paper is also commonly made from cotton and rag waste. This has the advantage of being lignin-free, but because there is much less cotton and rag than trees, it also tends to be much more expensive than wood pulp paper. You will still need to purchase from a reliable source though, since even rag paperand card can contain undesirable additives.L) A reliable source for quality rag papers is a recognized art stockiest. Many water color artists insist on using only fine quality rag paper and board.M) The main lesson to learn from this information is that you cannot rely on purchasing archival materials from the high street. The only safe solution is to purchase from specialist suppliers. It may cost rather more, but in the end you will know that your important and valuable data and images have the best home possible.1. The corn-flake packet is cheaper than high grade card.2. There are a lot of materials which can be used for making paper, but the superiority ones are soft wood, cotton and rags.3. During the whole manufacturing process, the final product is made froma pulp of cellulose fibres.4. In order to make white paper and card, the makers will add bleach.5. Liguin is essential for the tree but it will make paper easy to break.6. Many paper producers will preserve lignin during manufacture, because leaving the lignin will make more paper from a tree.7. Acid is particularly harmful to photographic materials.8. If the lignin is removed from the paper, the paper will be more expensive.9. Although free of lignin, paper made from cotton and rag waste can also cost more money than wood pulp paper because there is much less cotton and rag than trees.10. What we can learn from "Paper from Rag" is that you had better buy archival materials from specialist suppliers.2020年6月大学英语六级长篇阅读练习题（4）Definitions of ObesityA: How does one define when a person is considered to be obese and not just somewhat overweight? Height-weight tables give an approximate guideline as to whether one is simply overweight or has passed into the obese stage.B: The World Health Organization recommends using a formula that takes into account a person's height and weight. The "Body Mass Index" (BMI) is calculated by dividing the person's weight in kilograms by the square of their height in meters, and is thus given in units of kg/m2. A BMI of 18.5-24.9 is considered to be the healthiest. A BMI of between 25 and 29.9 is considered to be overweight, while a BMI of over 30 is considered to be obese.C: However, it is recognized that this definition is limited as it does not take into account such variables as age, gender and ethnic origin, the latter being important as different ethnic groups have very different fat distributions. Another shortcoming is that it is not applicable to certain very muscular people such as athletes and bodybuilders, who can also have artificially high BMIs. Agencies such as the National Cholesterol Education Program (NCEP) in the USA and the International Diabetes Foundation (IDF) are starting to define obesity in adults simply in terms of waist circumference.Health Effects of ObesityD: Over 2000 years ago, the Greek physician Hippocrates wrote that "persons who are naturally very fat are apt to die earlier than those who are slender". This observation remains very true today. Obesity has a major impact on a person's physical, social and emotional well-being. It increases the risk of developing diabetes mellitus type 2 ("mature onset diabetes") and also makes Type 2 diabetes more difficult to control. Thus weight loss improves the levels of blood glucose and blood fats, and reduces blood pressure. The association between obesity and coronary heart disease is also well-known.CancerE: Furthermore, in 2001 medical researchers established a link between being overweight and certain forms of cancer, and estimated that nearly 10,000 Britons per year develop cancer as a result of being overweight. This figure was made up of 5,893 women and 3,220 men, with the strongest associations beingwith breast and colon cancers. However, it is thought that being overweight may also increase the risk of cancer in the reproductive organs for women and in the prostate gland for men.F: The link between breast cancer and nutritional status is thought to be due to the steroid hormones oestrogen and progesterone, which are produced by the ovaries, and govern a woman's menstrual cycle. Researchers have found that the more a woman eats, or the more sedentary her lifestyle, the higher are the concentrations of progesterone. This link could explain why women from less affluent countries have lower rates of breast cancer. Women from less affluent nations tend to eat less food and to lead lifestyles which involve more daily movement. This lowers their progesterone level, resulting in lower predisposition to breast cancer.G: The Times newspaper, in 2002 reported that obesity was the main avoidable cause of cancer among non-smokers in the Western world!AgingH: Research published by St Thomas' Hospital, London, UK in 2005 showed a correlation between body fat and aging, to the extent that being obese added 8.8 years to a woman's biological age. The effect was exacerbated by smoking, and a non-overweight woman who smokes 20 cigarettes a day for 20 years added 7.4 years to their biological age. The combination of being obese and a smoker added at least ten years to a woman’s biological age, and although the study only involved women, the lead researcher Professor Tim Spector believes the finding would also apply to men.I: The aging effect was determined by measuring the length of telomeres, tiny "caps" on the ends of chromosomes, which help protect the DNA from the ageing process. Indeed, telomeres have been dubbed the "chromosomal clock" because, as an organism ages, they become progressively shorter, and can be used to determine the age of the organism. Beyond a certain point, the telomere becomes so short that it is no longer able to prevent the DNA of the chromosome from falling apart. It is believed that excess body fat, and the chemicals present in tobacco smoke release free radicals which trigger inflammation. Inflammation causes the production of white blood cells which increases the rate of erosion of telomeres.DementiaJ: Recent research (2005) conducted in the USA shows that obesity in middle age is linked to an increased risk of dementia, with obese people in their40s being 74% more likely to develop dementia compared to those of normal weight. For those who are merely overweight, the lifetime risk of dementia risk was 35% higher.K: Scientists from the Aging Research Centre at the Karolinska Institute in Sweden have been able to take information such as age, number of years in education, gender, body mass index, blood pressure level, physical activity and genetic factors, assigning each a risk score. They then used this information to devise a predictive test for dementia. This test will enable people at risk, for the first time, to be able to affect lifestyle changes which will reduce their risk ofcontracting dementia.Other ProblemsL: The world-wide upsurge in obesity, particularly in children, is of major economic concern, liable to drain economies. Of further concern is that research conducted in Australia and published in 2006, shows that up to one third of breech pregnancies were undetected by the traditional "palpation" examination, the danger being greatest for those women who are overweight or obese—a growing proportion of mothers. This means that such women are not getting the treatment required to turn the baby around in time for the birth, and in many cases require an emergency Caesarean section.M: This is a true health-care crisis, far bigger than Severe Acute Respiratory Syndrome (SARS) and ultimately, even bigger than AIDS.1. You can judge whether one is simply overweight or has passed into the obese stage according to the height-weight table.2. Using the "Body Mass Index"to define a person's weight ideal is limited, because it does not takes into account many variables such as age, gender and ethnic origin.3. A person's emotional well-being would be affected by obesity.4. Obesity has something to do with cancer in the prostate gland for man.5. Women from less affluent nations tend to have much less breast cancer.6. A non-overweight woman who smokes 20 cigarettes a day for 20 years added7.4 years to her biological age.7. The excess body fat, like the chemicals present in tobacco smoke, can lead to inflammation.8. Obese people in middle age run an increased risk of dementia .9. The predictive test for dementia will help people to affect lifestyle changes that will reduce their risk of contracting dementia.10. The world-wide upsurge in obesity, particularly in children, will possibly drain economies.。
2020年6月大学英语六级阅读晨读美文：Population Growth
2020年6月大学英语六级阅读晨读美文：Population GrowthThe growth of population during the past few centuries is no proof that population will continue to grow straight upward toward infinity and doom. On the contrary, demographic history offers evidence that population growth has not been at all constant. According to paleoecologist Edward Deevey, the past million years show three momentous changes. The first, a rapid increase in population around one m illion B.C., followed the innovations of tool making and tool using. But when the new power from the use of tools has been exploited, the rate of world population growth fell and became almost stable. The next rapid jump in population started perhaps 10,000 years ago, when mankind began to keep herds, plow and plant the earth. Once again when initial productivity gains had been absorbed, the rate of population growth abated. These two episodes suggest that the third great change, the present rapid growth, which began in the West between 250 and 350 years ago, may also slow down when, or if, technology begins to yield fewer innovations. Of course, the current knowledge revolution may continue without foreseeable end. Either way - contrary to popular belief in constant geometric growth - population can be expected in the long run to adjust to productivity. And when one takes this view, population growth is seen to represent economic progress and human triumph rather than social failure.。
幼儿小学英语-海洋动物Seaanimals
要点三
Invertebrates
Marine invertebrates include animals like octopus, squid, and sea stars. They do not have a backbone and have special body parts to help them move and survive in the water.
力。
培养环保意识
通过了解海洋动物和它们的生存 环境，孩子们可以更加关注环境
Marine animals are adapted to living in the saltwater environment and have special physical and behavioral characteristics to survive there.
Ty of marine animals
要点二
Mammals
Marine mammals are animals like whales, dolphins, and seals. They have fur or blubber and are airbreathing, but they have adapted to live in the ocean.
Tidal pools
Tidal pools are small bodies of water that form at low tide on rocky shores. They provide habitats for a variety of marine animals, including crabs, mollusks, and seaweed.
海洋哺乳动物【英文】
Marine Mammals
• All marine mammals arose from land ancestors and have become adapted to a marine existence • Streamlined body shapes reduce drag • Limbs have been modified into flippers • Evolved means of retaining large quantities of oxygen to facilitate long dives • Concentrated (highly saline) urine
Crabeater seal
Weddell seal
Leopard seal
Crabeater seal
Sea lions and fur seals
• Sea lions and fur seals (eared pinnipeds; family Otariidae) have 15 representative species
Marine Mammals
• In the United States, marine mammals are protected by the Endangered Species Act of 1985 and the Marine Mammal Protection Act of 1972 • Prohibits the capture, harming and/or killing of any marine mammal
Harbor Seal
Harp Seal
Hooded Seal
Marine Mammals
2020年6月大学英语六级阅读晨读美文：Cells and Temperature
2020年6月大学英语六级阅读晨读美文：Cells andTemperatureCells cannot remain alive outside certain limits of temperature, and much narrower limits mark the boundaries of effective functioning. Enzyme systems of mammals and birdsare most efficient only within a narrow range around 37 ℃; a departure of a few degrees from this value seriously impairs their functioning. Even though cells can survive wider fluctuations, the integrated actions of bodily systems are impaired. Other animals have a wider tolerance for changes of bodily temperature. For centuries it has been recognized that mammals and birds differ from other animals in the way they regulate body temperature. Ways of characterizing the difference have become more accurate and meaningful over time, but popular terminology still reflects the old division into "warm blooded" and "cold blooded" species; warm-blooded included mammals and birds whereas all other creatures were considered cold-blooded. As more species were studied, it became evident that this classification was inadequate. Afence lizard or a desert iguana -- each cold-blooded --usually has a body temperature only a degree or two belowthat of humans and so is not cold. Therefore the next distinction was made between animals that maintain a constant body temperature, called home otherms, and those whose body temperature varies with their environment, called poikilo therms. But this classification also proved inadequate, because among mammals there are many that vary their body temperatures during hibernation. Furthermore, many invertebrates that live in the depths of the ocean neverexperience a change in the chill of the deep water, and their body temperatures remain constant.。
2020年6月英语六级阅读真题及答案
2020年6月英语六级阅读真题及答案2020年6月英语六级阅读真题及答案Section ADirections：In this section, there is a passage with ten blanks,You are required to select One word for each blank from a list of choices given in a word bank following the passage.Read the passage through carefully before making your choices. Each choice in the bamk is identified by aletter.Please mark the corresponding letter for each item on Answer Sheet 2 with a single line through the centre You may not use any of the words in the bank more than once.For investors who desire low risk and guaranteed income,U.S. Government bonds are a secure investment because these bonds have the financial backing and full faith and credit of the federal government.Municipal bonds,also secure,are offered by local governmengts and oftenhave____36______such as tax-free interest.Some may even be____37______.Corportate bonds are a bit more risky.Two questions often_____38_____first-time corportate bond investors.The first is”If I purchase a corportate bond,do I have to hold it until the matueity date?”The answer isno.Bonds are bought and sold daily on ____39_____securities exchanges.However,if your bond does not have____40_____ that make it attractive to other investors, you may be forced to sell your bond at a____41____i.e., a price less than the bond’s face value. But if your bond is highly valued byother investors, you may be able to sell it at a premium,i.e., a price above its face value. Bond pricesgcncrally____42____ inversely (相反地)with current market interest rates. As interest rates go up, bond pnccs tall, and vice versa (反之亦然).Thus, like all investments，bonds have a degree of risk.The second question is “How can I ___43_______ the investment risk of a particular bond issue?” Sta ndard & Poor’s and Moody’s Investors Service rate the level of risk of many corporate and government bonds. And ____44______, the higher the market risk of a bond，the higher the interest rate. Investors will invest in a bond considered risky only if the _____45_____return is high enough.注意：此部分试题请在答题卡2上作答。
2020年6月英语六级考试阅读真题及答案
2020年6月英语六级考试阅读真题及答案2020年6月英语六级考试阅读真题及答案Section ADirection： In this section, there is a short passage with 5 questions or incomplete stamens. Read the passage carefully. Then answer the questions or complete the statements in the fewest possible words. Please write your answer on Answer Sheet 2.Question 47 to 51 are based on the following passageHighly proficient musicianship is hard won. Althoughit’s often assumed musical ability us inherited, there’s abundant evidence that this isn’t the case. While it seems that at birth virtually everyone has perfect pitch, the reasons that one child is better than another are motivation and practice.Highly musical children were sung to more as infants and more encouraged to join in song games as kids than less musical ones, long before any musical ability could have been evident. Studies of classical musicians prove that the best ones practiced considerably more from childhood onwards than ordinary orchestral players, and this is because their parents were at them to put in the hours from a very young age.The same was true of children selected for entry to specialist music schools, compared with those who were rejected. The chosen children had parents who had very actively supervised music lessons and daily practice fromyoung ages, giving up substantial periods of leisure time to take the children to lessons and concerts.The singer Michael Jackson’s story, although unusually brutal and extreme, is illumination when considering musical prodigy(天才). Accounts suggest that he was subjected to cruel beatings and emotional torture ,and that he was humiliated (羞辱) constantly by his father, What sets Jackson’s family apart is that his father used his reign of terror to train his children as musicians and dancers.On top of his extra ability Michael also had more drive. This may have been the result of being the closest of his brothers and sisters to his mother. “He seemed different to me from the other children —special,”Michael’s mother said of him. She may not have realized that treating her son as special may have been part of the reason be became like that.All in all, if you want to bring up a Mozart or Bach, the key factor is how hard you are prepared to crack the whip. Thankfully, most of us will probably settle for a bit of fun on the recorder and some ill-executed pieces of music-on the piano from our children.注意：此部分试题请在答题卡2上作答。
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Since there is such an abundance of food in the sea, it is understandable that some of the efficient, highly adaptable, warm-blooded mammals that evolved on land should have returned to the sea. Those that did have flourished. Within about 50 million years -- no time at all, geologically speaking -- one of the four kinds of mammals that has returned to a marine environment has developed into the largest of all animal forms, the whale. A second kind, the seal, has produced what is probably the greatest population of large carnivorous mammals on Earth. This suggests that these "top dogs" of the ocean are prospering and multiplying. However, such has not been the case, at least not for the last 150 years. Trouble has closed in on these mammals in the form of equally warm-blooded and even more efficient and adaptable predators, humans. At sea, as on land, humans have now positioned themselves on the top of the whole great pyramid of life, and they have caused serious problems for the mammals of the sea. There is a simple reason for this. Marine mammals have the misfortune to be swimming aggregates of commodities that humans want: fur, oil and meat. Even so, they might not be so vulnerable to human depredation if they did not, like humans, reproduce so slowly. Every year humans take more than 50 million tons of fish from the oceans without critically depleting the population of any species. But the slow-breeding mammals of the sea have been all but wiped out by humans seeking to satisfy their wants and whims.。