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    If we are observant(善于观察的), we can find that most of the flowers in nature are red, orange and yellow. If we have seen a black flower, it is a chance in a million. People have made census (统计) to colors of more than four thousand kinds of flowers and discovered that only eight of them are black. Why are black flowers so rare?

    As we know, sunlight is formed by seven different kinds of colored light. The wave length of each light changes, so the quantity of heat in each light changes, too. Flowers, especially their petals (花瓣) , are very weak and easy to the harm caused by high temperature. Black flowers can take in all the light waves, which cause the flowers to dry up in a high temperature. So the black flowers can hardly continue their lives. While red flowers, orange flowers and yellow ones can protect themselves from sunlight by reflecting（反射） the red light, orange light and yellow light, each of which has a large quantity of heat.

    That is why red, orange and yellow flowers are very common in nature while black flowers are so unusual.

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    Let's face it. No one drinks diet sodas for the taste. People drink diet sodas in the hope that it will help them lose weight or at least keep them from gaining it. Yet it seems to have exactly the opposite effect, according to a new study.

    Researchers from the University of Texas said those who drank two or more diet sodas a day had waist size increases that were six times greater than those who didn't drink diet sodas. ＂What we saw was that the more diet sodas a person drank, the more weight they were likely to gain,＂ said Sharon Fowler.

The study was based on data from 474 participants in a large, ongoing research project, where the participants were followed for nearly 10 years.

    While the findings are surprising, they also offer some explanations.

    Nutrition expert, Melanie Rogers, who works with overweight patients in New York, has found that when patients are switched from regular to diet sodas, they don't lose weight at all. ＂We weren't seeing weight loss necessarily, and that was confusing to us,＂ said Rogers.

    So why would diet soda cause weight gain? No one knows for sure yet, but it could be that people think they can eat more if they drink diet sodas, and so over-compensate for the missing calories.

    A related study found some sweeteners (甜味剂) raised blood sugar levels in some mice. ＂Data from this and other potential studies suggest that the promotion of diet sodas and artificial sweeteners may be risky,＂ said Helen P. Hazuda, professor at the University of Texas's school of medicine. ＂They may be free of calories, but not of consequences.＂

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    Have you ever noticed that the more you have the more you want? Let's face it. Thinking our life is good enough doesn't come naturally to many people. When we have high expectations of everything in life we will run into disappointment. Only when we are aware that needs are different from desires can we live with satisfaction. Here are a few ideas to help you be happier with what you have and who you are.

    Focus on what you are thankful for. Most people want things to be better than they are, or when things are going well, we forget to appreciate what we have. Learn to reflect（反映）on how much better things are than they could be. Focus on what you are thankful for. Write down 5 things you are grateful for right now.

    When we hold onto regrets from decisions we have made, it can realty poison our well-being. Many people regret something they can no longer change, which ends up holding them back from moving forward in a more positive manner. What happened in the past is done and gone, so work to stay present and be mindful of the current （目前的）moment to find more joy and fulfillment（满足）.

    When we use other people as the measuring stick for our personal success and quality of life we are likely to be less satisfied. Social comparisons can provide useful information when we try to learn from others, but they also hold our perspective（观点）in a discontented position. Compare yourself less with others so you can be satisfied more.

    When you are focused on your big ambitions（抱负）and future goals you might elide the daily pleasures that surround you. Learn to slow down and absorb the wonder and beauty around you. Stay present and focus on the task you're doing at the moment. Don't let the life pass you by because you're always on the go and distracted（分心）by ambition.

    Practice looking at life through the lens of contentment（满意）and it will become more natural.

阅读理解

    Ottawa is the capital of Canada. It is the second largest city in Ontario and the fourth largest city in the country.

    The Centre Block is the main building on Parliament Hill (国会山). There also stand several ceremonial spaces, such as the Hall of Honor and the Memorial Chamber. The present Centre Block is the second copy of the building, after the first was undermined by a big fire in 1916, and it is one of the most recognizable buildings in Canada.

    Downtown Ottawa is the commercial and economic centre of the city. Most of the buildings are office towers. While most of Ottawa's high tech industry is based elsewhere, it has an important presence in the downtown center. The downtown also contains a number of apartments, hotels, and the older single family homes and townhouses along its edges (边缘).

    The National Gallery of Canada is one of Canada's earliest art galleries. The Gallery has a large and varied collection of paintings, drawings, sculpture and photographs. Although its focus is on Canadian art, it also holds works by some well-known American and European artists.

    The Rideau Canal is the oldest continuously operated canal (运河) system in North America. At the very beginning, it was used to provide a safe supply and communication route between Montreal and the British naval (海军的) base in Kingston. It remains in use today mainly for people to boat and enjoy themselves, with most of its original structures undamaged. The locks on the system open for navigation (航海) in mid-May and close in mid-October.

阅读理解

    This could be the perfect gift for the partner, who embarrasses you on the dance floor. Smart socks, which can teach to dance, may be the answer for anyone with two left feet.

    The socks have been developed as a running tool to help runners improve their skills. Thanks to the socks, users can accurately record not only how far and fast they run but also how well. It means the user maximizes their performance, and reduces damage to body and prevents hurt. The hi-tech socks are made of special fibers that watch the movements of your feet. They look, feel and can be washed like normal clothes.

    Sensors（传感器）record each movement and send it by an ankle transmitter（脚踝发射器）to a smart phone.  Then a "virtual coach" application shows the information and can tell the user what they are doing wrong, and help to improve skill in any task with feet.

    The socks should be useful to athletes and weekend joggers. "People think running is so easy and of course everybody can do it but not necessarily safely and well, "Dr Davide Vigano said. A recent study showed that between 60 and 80 percent of runners got hurt per year. This is pretty much more than any other human activity. Researchers say the technology can also be developed to teach people how to dance, play sports such as golf, or even to help to teach women to walk better in high heels.

    Mr. Vigano said, "People could all benefit from the idea. We have had interest from all sorts of sports, like skiing, football, cycling and golf. Anything where you have to use your feet can use it. It could even be put in high heels to help women walk in them safely. "

    Socks are just the start, and the technology could be used in gloves, hats and boots. The socks, anklet and software package, are expected to be sold for around￡120, which will go on sale in March.

阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。

    When athletes at the 2020 Tokyo Olympics collect their medals, they'll not only be wearing something that celebrates their sporting performance, but something that symbolizes lastingness. For both the 2020 Olympics and Paralympics, organizers aim to make all of the gold, silver, and bronze medals out of used electronics. This strong message about how to make use of e-waste has gotten a lot of Japan involved.

    Starting in April 2017, the Japanese Olympic Committee began collecting old laptops, digital cameras, smartphones, and other abandoned electronics. The initiative (倡议) has achieved great success. Already, the quantity needed for bronze medals has been met, and they're in the homestretch for silver and gold medals, meaning the collection process can pack up at the end of March.

    When looking just at the number of cell phones collected, the amount of waste is shocking. In a period of about 18 months, a little over 5 million smartphones were collected thanks to cooperation with NTT DOCOMO. Japan's largest mobile phone operator allowed the public to turn in phones at their shops, which counted a lot in the project's success.

    After being taken apart and sorted, the small electronics underwent a smelting process to extract (提炼) all the gold, silver, and bronze elements. Thanks to this initiative, the worldwide struggle with e-waste will have a global platform. According to a study published by the United Nations University—44.7 million metric tons of e-waste were made in 2016. Only 20% of that was actually recycled. Unfortunately, this figure is set to rise significantly in the coming years, moving to 52.2 million metric tons by 2021. So while the Tokyo Olympics initiative might be just a drop in the bucket, it's a good start in showing what the public can do if they're made more aware of the issue.

阅读理解

    LONDON­Britain prepares for a vote Thursday that will decide whether it leaves the European Union. The debate has centered on immigration and economic security. Both sides have lowered the tone of their arguments after a three­day suspension(暂停) of campaigning that followed the murder of an anti­Brexit lawmaker, an incident that polls(民意调查) suggest has shocked many previously undecided voters who now say they will vote to remain.

    These are uncertain times in a nation whose economy is the second largest in the European Union. The risks are huge. There are warnings that leaving the 28­member group may cause the British pound to lose 15 percent of its value and bring the resignation(辞职) of David Cameron, the country's prime minister; his stay or not depends on whether Britain listens to him and votes to remain.

    For months, the Leave campaign has been hitting the streets. Its arguments are based largely on immigration, and the belief that Britain has handed control of its borders(边界) to a European super state: "The U.K. has lost control over migration. We have to accept anyone into this country if they have an EU passport, no matter if they have a criminal record or not. We are not allowed to say 'no' to people and that is damaging for the security of the U.K., but it is also putting pressure on jobs and opportunities for young people," said Tom Harwood, a Brexit campaigner.

    The murder of Jo Cox, an anti­Brexit, pro­immigrant lawmaker by a far right extremist(极端分子) with a history of mental problems had a serious effect on both campaigns, and on voters.

    Polls since the June 16th murder showed the Leave camp losing ground, but with both sides still very close on a referendum(全民投票) that many believe could change the course of European history.

阅读理解

    As a young boy, I knew what people said was not always what they meant or were feeling. And I knew it was possible to get others to do what I wanted if I read their real feelings and responded(回应) suitably to their needs. At the age of eleven, I sold sponge rubber(泡沫橡胶) door-to-door after school and quickly worked out how to tell if someone was likely to buy from me. When I knocked on a door, if someone told me to go away but their hands were open and they showed their palms (the inside surfaces of their hands), I knew it was safe to continue with my presentation(展示) because they weren't angry or threatening although they may have a dismissive(不屑 ) attitude. If someone told me to go away in a soft voice but used a pointed finger or closed hand, I knew it was time to leave.

    As a teenager, I became a pots and pans(炊具)salesperson, and my ability to read people earned me enough money to buy my first house. Selling gave me the chance to meet people and study them close and to know whether they would buy or not, simply by watching their body language.

    I joined the life insurance business at the age of twenty. And I went on to break several sales records for my company, becoming the youngest person to sell over a million dollars' worth of business in my first year. This achievement allowed me to become a member of the well-known Million Dollar Round Table (MDRT, which recognizes the world's top achievers in life insurance). I was lucky that the skills I'd learned as a boy in watching body language while selling pots and pans could be used in this new area, and were directly related to the success I could have in any business closely connected with people.

阅读理解

    I became a magician by accident. When I was nine years old, I learned how to make a coin disappear. I'd read The Lord of the Rings and risked coming into the adult section of the library to search for a book of spells (魔法) — nine being that curious age at which you're old enough to work through more than 1, 200 pages of mysterious fantasy literature but young enough to still hold out hope that you might find a book of real, actual magic in the library. The book I found instead taught basic sleight-of-hand (戏法) technique, and I devoted the next months to practice.

    Initially, the magic wasn't any good. At first it wasn't even magic; it was just a trick — a bad trick. I spent hours each day in the bathroom running through the secret moves in front of the mirror. I dropped the coin over and over, a thousand times in a day, and after two weeks of this my mom got a carpet sample from the store and placed it under the mirror to eradicate the sound of the coin falling again and again.

    I had heard my dad work through passages of new music on the piano, so I knew how to practice — slowly, deliberately, going for precision rather than speed. And then I tried the illusion (错觉) in the mirror and an unbelievable scene took place. It did not look like a magic trick. It looked like a miracle. I knew that I had got what I wanted.

    One day I made the performance on the playground. We had been playing football and were standing by the backstop in the field behind the school. A dozen people were watching. I showed the coin to everyone. Then it disappeared. The kids screamed. They yelled, laughed, scrambled away. Everyone went crazy. This was brilliant.

Choose the one that fits best according to the information given in the passage you have just read.

    Fifty four years ago, young Quentin entered this world. "Action!" he must have yelled then to his mum. When he was two, his whole family moved to Los Angeles, and before Quentin Tarantino turned a teenager, he had already seen more movies than most people. In his twenties he started working at the Manhattan Beach Video Archives, where he made some important friendships and tried his hand at making a first movie. It would take another few years until he would sell the scripts for True Romance and Natural Born Killers, and shortly after go on and conquer the film festival circuit in a storm with Reservoir Dogs. And so it began…

    With Pulp Fcition, QT finally turned Hollywood upside-down for good, and established himself as, what they would then call, an "enfant terrible" of the new film-making community to this day, Pulp Fiction counts as a completely original masterpiece, that sometimes even to his most loyal fans he has not matched again. After Jackie Brown, he took a pause for a while, not turning out a major motion picture until Kill Bill. Kill Bill turned into an epic, and manifested director Tarantino as the truly great filmmaker, opening the eyes of millions among the younger generations to lost classics, foreign cult cinema and the wild world of exploitation film.

    Then in 2007, he made Grindhouse together with his long time friend Robert Rodriguez. The movie was well-received among critics, but was a financial disaster. Tarantino has talked about a war movie for many years, but not until 2008 did any of those rumors come together, when he announced that he had in fact finally finished a script for Inglourious Basterds, a massive war epic. The movie went into production that same year, starring Brad Pitt in the leading role. It was a huge international success and gathered quite a few awards.

    In 2011, Tarantino announced the completion of his latest script, a movie about slavery in the old US south of the 1860s, titled Django Unchained. The movie has attracted enormous attention, especially because it stars Jamie Foxx, Leonardo DiCaprio, Samuel L. Jackson and Christoph Waltz, who won an Oscar for his role in Inglourious Basterds, and whose acting talents have been truly recognized. And 2015 marked the release of his 8th film, appropriately titled The Hateful Eight, a post Civil War era Western mystery and thriller.

    At the age of 54, Quentin Tarantino has recently gone on record saying he will retire some time soon, but all of the movie fans definitely hope the speak of film-making stays strong in his heart of a long time still. Because in a world densely crowded with average filmmakers QT seems to be one of the few who never play it safe.

A Salute to Quentin Tarantino

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    Traditional Chinese medicine (TCM) is an ancient form of healthcare that dates back over 2,500 years, which aims to prevent or cure disease by maintaining or restoring yinyang balance. Fundamentally, TCM seeks to restore a dynamic balance between two complementary forces, yin (passive) and yang (active). According to the yinyang theory, a person is healthy when harmony exists between these two forces; illness, on the other hand, results from a breakdown in the balance.

    TCM practitioners (从业者)look to treat the root cause of disease and take a holistic approach to helping people experience complete recovery without the use of conventional drugs. TCM is "holistic”' because it takes into account all aspects of a patient's life, rather than just several obvious symptoms. TCM practitioners view the body as a complex system, rather than separate organs. They use smell, hearing, touch, and pulse diagnosis (诊断)to discover the source of an unbalanced health condition. In addition, the practitioner typically makes use of what is known as five phases (wuxing). Using the five-phase theory, the practitioner can create a plan for treatment that might contain such components as herbs, lifestyle changes, and foods for recovery.

    Over the past several decades, TCM has been going global. It is now practiced in 183 countries and regions with 86 of them signing agreements with China to promote it. More and more medical schools are now recognizing the importance of training students and staff in "mind-body" practices that emphasize disease prevention and holistic treatments. A study of 3,200 physicians, conducted by Health Products Research, indicates that more than 50 percent of physicians in the U.S. planned to begin or increase use of TCM.

阅读理解

    Scientists often complain that people are not rational (理性的) in their opposition to technologies such as nuclear power and genetically modified (GM) crops. From a statistical perspective, these are very safe, and so people's fear can be explained only by emotion, strengthened by ignorance. Electricity from nuclear power has led to far fewer direct deaths than has coalfired power, yet many people are afraid of it, and hardly anyone is afraid of coal plants. Similar arguments can be made about GM crops, which studies have shown are generally safe for most people to eat.

    Scientific illiteracy (无知) may be part of the problem. Most of us are afraid of things we don't understand, and studies have shown that scientists tend to be more accepting of potentially risky technologies than laypeople. This suggests that when people know a lot about such technologies, they are usually reassured.

    But there's more to the issue than meets the eye. It is true that many of us fear the unknown, but it is also true that we don't care enough about routine risks. Part of the explanation is complacency: we tend not to fear the familiar, and thus familiarity can lead us to underestimate risk. The investigation into the Deepwater Horizon blowout and oil spill (原油泄漏) in 2010 showed that complacency—among executives, among engineers and among government officials—was a major cause of that disaster. So the fact that experts are unworried about a threat is not necessarily reassuring.

    Scientists also make a mistake when they assume that public concerns are wholly or even mostly about safety. Some people object to GM crops because these crops facilitate the increased use of chemicals. Others have a problem with the social impacts that switching to GM organisms can have on traditional farming communities or with the political implications of leaving a large share of the food supply in the hands of a few corporations.

    Geoengineering (地球工程学) to lessen the impacts of climate change is another example. Laypeople as well as scientists are more concerned about oversight (监管) than safety. Who will decide whether this is a good way to deal with climate change? If we undertake the project of setting the global temperature by controlling how much sunlight reaches Earth's surface, who will be included in that "we" and by what process will the "right" global temperature be chosen?

Can we say which group's view is closer to an accurate assessment?

阅读理解

White-collar workers increasingly unhealthy

    An increasing number of white-collar workers in Shanghai are getting failing grades on their physical examinations, according to a white paper on the health of white-collar workers in Shanghai.

    Carried out by Shanghai Foreign Service Group, a human resources company, the report indicated that more than 53 percent of males are overweight, 46 percent suffer from a fatty live and about 26 percent have elevated blood lipids (血脂). However, females are more often diagnosed as having breast lesions (乳房病变) that could lead to cancer (85 percent), thyroid (甲状腺) disorder (34 percent) and hemorrhoids (痔疮) (23 percent).

    Though the report also found that white-collar workers were paying increasing attention to their health—with about 84 percent saying they followed their condition closely or very closely—those with healthy lifestyles dropped to 64 percent last year from 77 percent in 2015.

    The report came from about 500,000 physical exams taken by while-collar workers in Shanghai over the past five years. “I always eat and drink too much and never exercise,” said Wei Ruoxi, a 26-year-old working in finance who is struggling with being overweight. “I know what a healthy lifestyle looks like, but the job just brings too much pressure and squeezes out exercise time,” she added. Hu Xiaolong, 30, an accountant in Shanghai, said he was determined to live healthily from now on. “My recent physical examination shows a little shadow in the lung, which startled me when I heard it. I really need to quit bad habits like smoking and staying up late.”

    The white paper also showed that more people are turning to commercial health insurance to cope with financial risks caused by health problems. The popularity of insurance purchases among the participants reached 15.3 percent last year, a rise of 4 percentage points in just one year. Most participants also expected their companies to help them with effective health management, such as offering membership cards for gyms, flexible working schedules and regular physical examinations.

阅读理解

I have dreamt of taking a trip to Hawaii since I graduated, but the best thing always needs waiting. I took a trip with my friends to Haleakala National Park, which lies in Hawaii.

When we arrived at Haleakala National Park, we were advised to watch the early morning sunrise. I was lost in the sightseeing (观光) that afternoon, so I could hardly wait to see the sunrise. The next morning, we all got out of bed very early and got to the seaside at 3 o'clock. In the first half an hour, we imagined how wonderful it would be when the first light came out through the thick clouds and how soft it would be when the light touched our skin, so we waited and waited. However, another half an hour later, I gradually lost my patience since there was nothing but the chilly darkness, and I felt that I was frozen to death. But my friends were still extremely cheerful.

Nearly another one hour later, "Amazing!" Judy burst out and we all shouted to welcome the light, which was really unbelievable. Until today, I dare say that it is the most impressive sunrise in my life. However, waiting in the morning darkness is also one memory I can't forget forever.

Waiting sometimes is really a hard thing for most of us as it needs patience and strong ­willed determination (决心) , but what about the result after that? It might turn out to be pleasing and unbelievable. So, it is really worth waiting for the best.

阅读理解

Climate change leads to a threat to the world's sandy beaches, and as many as half of them could disappear by 2100, a new study has found. Even by 2050 some coastlines could be unrecognizable from what we see today, with 10% to 12% facing severe erosion (侵蚀).

Using updated sea level rise predictions, the researchers analyzed how beaches around the world would be in a future with higher seas and more damaging storms. They also considered natural processes like wave erosion, as well as human factors-like coastal building developments, all of which can affect a beach's health. The study found that sea level rise is expected to outweigh these other factors, and that the more heat-trapping gases humans put into the atmosphere, the worse the influences on the world's beaches are likely to be.

It's hard to overstate just how important the world's beaches are. They cover more than one third of the world's coastlines, and protect coastal areas from storms. Beaches are also important economic engines, supporting relaxation, tourism and other activities. And in some areas, the beach is more than a vacation destination. In places like Australia, life near the coast revolves around the beach for much of the year.

Some of the world's most popular beaches are already taking action. Places like Miami Beach are trucking in thousands of tons of sand to patch up (修复) badly eroded shorelines, while others have built sea walls and breakwaters in an attempt to hold precious sand in place. But the financial and environmental costs of these projects are huge, and scientists say rising seas and more powerful storms, supercharged by a warmer climate, will make this a losing battle.

However, the researchers did find that humans have some control over what happens to the world's beaches. If the world's governments are able to stick to modest cuts to heat-trapping gas pollution, the researchers found that 22%of projected beach losses by 2050 could be prevented, a number that grows to 40%by 2100 if greenhouse gases are limited.

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There are so many choices when you go shopping. You have to check the sell — by dates so that you know how long you can store and use the food you are purchasing.

But do you know that the best sell — by dates on food packaging don't really tell you if the food is safe to eat. The food may not last as long as it says if it isn't stored correctly at any point of the distribution chain. Now there is food packaging that can detect and change colors if the food has gone bad.

Each American wastes 103 pounds of spoiled food out of the refrigerator every year. The new smart packaging from Primitives Biodesign—a new company that operates out of a lab at Indibio, a biotech accelerator in San Francisco-can help to reduce this huge waste of food.

The basic material that doesn't contain sensing material is made from algae and can block oxygen more effectively than regular film, so the food stays fresher for a longer time. Since it is made from a natural substance, it can also break down in nature.

Making the film smart is the thorny part. Luckily, the team managed to use a process that is like the way nature responds to changes in the environment. The mechanism responds like the way flowers emit compounds to change colors.

"It could be supplement packaging that indicate when it's been tampered with by changing color to tell you that it's no ledger safe," says Kan. She explained that the new packaging can be used on food products to fell if the food has turned bad before someone has to smell or taste it.

The company has proven in lab tests that the technology works and now they are working on how to develop commercial uses for it. The added safety features will come out later. Helping to control food waste in products like meat or cheese which have high greenhouse gas emissions will also help to reduce climate change.

阅读选择

Researchers say they have translated the meaning of gestures that wild chimpanzees (黑猩猩) use to communicate. They say wild chimps communicate 19 specific messages to one another with a "vocabulary" of 66 gestures. The scientists discovered this by following and filming groups of chimps in Uganda, and examining more than 5,000 incidents of these meaningful exchanges.

Dr Catherine Hobaiter, who led the research, said that this was the only form of intentional communication to be recorded in the animal kingdom. Only humans and chimps, she said, had a system of communication where they deliberately sent a message to another group member.

"That's what's so amazing about chimp gestures," she said. "They're the only thing that looks like human language in that respect. ”

Although previous research has shown that apes and monkeys can understand complex information from another animal's call, the animals do not appear to use their voices intentionally to communicate messages. This was a significant difference between calls and gestures, Dr Hobaiter said.

Chimps will check to see if they have the attention of the animal with which they wish to communicate. In one case, a mother presents her foot to her crying baby, signaling:" Climb on me. " The youngster immediately jumps on to its mothers back and they travel off together. "The big message from this study is that there is another species (物种) out there. that is meaningful in its communication, so that's not unique to humans," said Dr Hobaiter.

Dr Susanne Shultz, an evolutionary biologist from the University of Manchester, said the study was praiseworthy in seeking to enrich our knowledge of the evolution of human language. But, she added, the results were "a little disappointing".

"The vagueness of the gesture meanings suggests either that the chimps have little to communicate, or we are still missing a lot of the information contained in their gestures and actions," she said. "Moreover, the meanings seem to not go beyond what other animal convey with non-verbal communication. So, it seems the gulf remains. "

阅读下列短文，从每题所给的A、B、C和D四个选项中，选出最佳选项。

As it turns out, comfort food, instead of comforting you, may actually be linked to your mental comfort but cause you to become depressed. One of the main reasons for eating junk food is stress eating, but now new research has also suggested ifs harming your mental health too.

Junk food, fast food and so-called “healthy snack options” are all big business nowadays because they provide convenient options for people on the go. The decision when choosing a snack of going for what you want, over what you need, plays an important part in your overall mental health.

Researchers at Cardiff University believe that reaching for unhealthy snacks when the stress of time-sensitive commitments, such as work or study, limits your choices of snacks, won't only destroy your fitness goals, but it can also negatively affect your mental health.

Scientists provided crisps, chocolate or a piece of fresh fruit to test subjects before measuring their effects on mental comfort. The results were amazing. Those snacking on crisps and chocolate showed greater symptoms(症状) of depression, anger and emotional disorders in only 10 days. The increase was an unbelievable 47% in depressive parts. The subjects that snacked on fruit experienced none of these symptoms. In fact, on the contrary, they became 32% less anxious.

While the researchers didn't point out exactly why the fruit group felt so much happier, the answer may lie in fruit's ability to increase the brain's production of serotonin, which is commonly known as a feel-good neurotransmitter(神经递质) that can help to bring about a happier state of mind and reduce anxiety.

The best results you can take away from the study is that when you're hungry you should always be well prepared with healthy snacks that will not only fill you up but will also positively affect your mental health and keep you focused all day long.

阅读理解

It may not be quite old enough to be the world's oldest living organism—that "honor" goes to the bristlecone pine tree (aged 5, 000 years)—but, at 4, 000 years of age, Leiopathes glaberrima, a deep-water coral species, does set the record for being the oldest animal living under the sea.

Located on the floor of the Pacific Ocean, off Hawaii, the 3 meters tall, (extremely) long-lived "black coral" could have some valuable clues about past incidents of climate change;  specifically, it could better scientists' understanding of how oceans draw down carbon dioxide—and of ocean acidification in general. Brendan Roark of Texas University, who led a research expedition in 2006 to study the corals' climate records, presented his findings at the recent AAAS meeting.

How long they can live is anybody's guess, Roark told Science's Erik Stokstad and his colleagues used radiocarbon dating to determine the coral's age. What this suggests, he said, is that the harvesting of deep-water coral for jewelry should be completely banned;  because the corals grow at such an anemic(贫血的) rate, any level of harvesting would likely wipe out the remaining specimens—those not yet affected by ocean acidification.

Roark believes it could be possible to reconstruct records of subsurface temperature variability and ocean circulation changes, which would provide some insight on climate change incidents and help predict future effects. By comparison, that ocean quahog clam we mentioned a while back—aged 405 years—seems almost sprightly.

阅读短文，回答问题

The African elephant, the largest land animal remaining on Earth, is of great importance to African ecosystem(生态系统). Unlike other animals, the African elephant is to a great extent the builder of its environment. As a big plant-eater, it largely shapes the forest-and-savanna(稀树草原) surroundings in which it lives, therefore setting the terms of existence for millions of other animals that live in its habitat.

It is the elephant's great desire for food that makes it a disturber of the environment and an important builder of its habitat. In its continuous search for the 300 pounds of plants it must have every day, it kills small trees and underbrushes, and pulls branches off big trees. This results in numerous open spaces in both deep tropical forests and in the woodlands that cover part of the African savannas. In these open spaces are numerous plants in various stages of growth that attract a variety of other plant-eaters.

Take the rain forests for example. In their natural state, the spreading branches overhead shut out sunlight and prevent the growth of plants on the forest floor. By pulling down trees and eating plants, elephants make open spaces, allowing new plants to grow on the forest floor. In such situations, the forests become suitable for large hoofed plant-eaters to move around and for small plant-eaters to get their food as well.

What worries scientists now is that the African elephant has become an endangered species. If the elephant disappears, scientists say, many other animals will also disappear from vast areas of forest and savanna, greatly changing and worsening the whole ecosystem.