Coral reefs are,in fact,a necessary part of our ecosystem and provide opportunities for human beings to gain a better understanding of the ocean.Unfortunately,they're also disappearing faster than ever.

    According to a warning by the US National Oceanic and Atmospheric Administration(NOAA) on Oct.8,the world is in its third recorded global coral bleaching（白化）since 1998 and 2010.This means no place with coral has been spared,as coral reefs are coming into contact with increasingly warm seas,which is leading to them dying off in large numbers.

    Coral bleaching is like human cancer.It happens when corals are under stress from changes in light,nutrients,or temperature.This causes the coral to drive away the symbiotic algae（共生藻类）,living within their tissues（组织）, which play an important role in providing food for coral while making it colorful.Without the algae,coral reefs become pale and weak.In some cases they are not able to recover and eventually die off.

    The current coral bleaching event started back in late 2014 and continued into this year with no signs of stopping.The BBC reports that 35% of coral reefs in the world will likely be affected,and an estimated 4,633 square miles (about 120,000 square kilometers) of coral reefs could die.

    The loss of coral reefs is no small matter.Although they only take up 0.1% of the ocean floor,coral is home to about 25% of marine life.This isn't just a problem for divers and fish,as Eakin pointed out.Coral reefs are important globally,he added,as they protect shorelines,produce money in tourism,and help provide food for 500 million people worldwide.So people cannot overlook the environmental,economic and social effects of the loss.

    The NOAA warning about coral bleaching came just about two months before a global climate summit（峰会）in Paris,where hundreds of world leaders will attempt to work out a plan to fight climate change.

    Oceans will be a key subject during the summit,and Eakin says there's an "absolutely urgent need" for action.

Study Habits You Should Be Practising

    With exams, essays, projects, and many deadlines for different things, effective（有效的）study habits are necessary. {#blank#}1{#/blank#} If you are in need of a bit of an improvement, keep reading for the top four study habits that you should be practicing.

    ⒈Make and use flashcards.

    {#blank#}2{#/blank#} By using flashcards with a question on one side and the answer on the other, you will force your brain to recall he necessary information. Even if you struggle a bit with a card, you will still be actively revising the necessary material.

    ⒉Revise, revise, revise!

    Many students put off studying until just before the exam, with the more hardworking students giving themselves a week or two before a test. {#blank#}3{#/blank#} It's best to revise the information a little bit every day, so that you are not upset when a test comes around.

    ⒊{#blank#}4{#/blank#}

    One of the most effective—and the most fun—methods of studying is to watch related lectures and videos in order to get more material. Watch documentaries or videos on YouTube and educational websites. You may be surprised at how much you can learn from videos, and just how much information is available online.

    ⒋Re-write your notes.

    Studies have shown that writing information out by hand increases your ability to remember the material. This makes the recall go hand-in-hand with muscle memory.{#blank#}5{#/blank#}

    These are the four most effective study habits, and something all successful students do. Make sure you are on top of your game by following these study methods!

    Babies teach their older brothers and sisters empathy (移情), according to a new research. Empathy means understanding and entering others' feelings. Until now, younger kids have generally been regarded to learn plenty from their older brothers or sisters but don't give back much. But this study, published in Child Development, confirms that younger siblings (兄弟姐妹) ensure their big brothers and sisters don't grow into disgusting people—no easy task.

    “Although it's assumed that older siblings and parents are the primary socializing influences on younger siblings' development but not vice versa, we found that both younger and older siblings positively contributed to each other's empathy over time,” study co-author Marc Jambon said in a statement. Prior sibling studies have focused on the influence of older brothers and sisters, probably because their impact is most obvious. As one review of literature notes, studies have shown that older siblings influence everything from their younger siblings' motor development to their risk of smoking later in life. And although separated studies have tried to pin down effects that younger siblings have on their older siblings, the influence of baby brothers and sisters remains unclear.

    For this new study, Jambon and his colleagues recruited (招募) a diverse group of 452 Canadian sibling pairs between the ages of 18 months and four years. At the start of the study, individual researchers assessed children's baseline empathy levels by visiting the kids at home and then pretending to hurt themselves or break a valuable item. Eighteen months later, they found small but significant increases in empathy.

    One unexpected exception—older sisters did not appear to experience increased empathy after 18 months living with their little brothers, specifically. The researchers aren't sure why this exception appeared, and they recommend that future studies dive into more complex phenomena.

    Eyesight is the sense that you rely upon the most. Since we live in a world that requires your eyes to routinely stare at the small type and images on cell phones, computer screens, and televisions, it is important for you to improve and protect your eyesight. {#blank#}1{#/blank#}

    Eyes are just like any other part of the body. {#blank#}2{#/blank#}Similar to other organs, a diet high in fruits and vegetables and low in sugar and fatty foods will go a long way in maintaining healthy eyes.

    {#blank#}3{#/blank#}Plan to exercise your eyes when you wake up, before going to bed, or when your eyes are tired. Make sure your hands are clean so that you do not hurt your eyes and your mind is relaxed before starting.

    Since you use your eyes every waking moment, give them lots of rest and relaxation by taking breaks throughout the day and getting enough sleep every night to fully rest, repair, and recover your vision. {#blank#}4{#/blank#} In the short term, it can cause eye strain (疲劳) or dry eyes. In the long term, it can lead to damage to the optic nerve (视觉神经), which can cause pain and damage your vision.

    Besides, most jobs nowadays involve some degree of computer usage, meaning almost everyone will be spending time in front of a computer. {#blank#}5{#/blank#}To avoid this, you'll have to properly try to limit your screen time by routinely taking breaks and exercising your eyes.

A. They need nutrition to function well.

B. Close your eyes when exercising your eyes.

C. A lack of sleep will weaken your vision health.

D. You can enjoy your vision for the rest of your life.

E. Unfortunately, this can result in eye strain or injury.

F. There are many ways to keep your eyesight healthy and sharp.

G. Exercising your eyes daily will help you maintain healthy eyes.

    Race walking shares many fitness benefits with running, research shows, while most likely contributing to fewer injuries. It does, however, have its own problem.

    Race walkers are conditioned athletes. The longest track and field event at the Summer Olympics is the 50-kilometer race walk, which is about five miles longer than the marathon. But the sport's rules require that a race walker's knees stay straight through most of the leg swing and one foot remain in contact (接触) with the ground at all times. It's this strange form that makes race walking such an attractive activity, however, says Jaclyn Norberg, an assistant professor of exercise science at Salem State University in Salem, Mass.

    Like running, race walking is physically demanding, she says, According to most calculations, race walkers moving at a pace of six miles per hour would burn about 800 calories(卡路里) per hour, which is approximately twice as many as they would burn walking, although fewer than running, which would probably burn about 1,000 or more calories per hour.

    However, race walking does not pound the body as much as running does, Dr. Norberg says. According to her research, runners hit the ground with as much as four times their body weight per step, while race walkers, who do not leave the ground, create only about 1.4 times their body weight with each step.

    As a result, she says, some of the injuries associated with running, such as runner's knee, are uncommon among race walkers. But the sport's strange form does place considerable stress on the ankles and hips, so people with a history of such injuries might want to be cautious in adopting the sport. In fact, anyone wishing to try race walking should probably first consult a coach or experienced racer to learn proper technique, she says. It takes some practice.

Brushing your teeth twice a day should keep the dentist away. But if a group of scientific researchers have their wish, it will make the rest of your body healthy too. A toothbrush that checks blood sugar and bacteria while you brush is currently in development in the USA. It is one of many gadgets (小器械) proposed by engineers and doctors at the Center for Future Health in New York.

The gadgets seem fanciful, but the basic principles are simple. The gadgets should make it easy for people to detect illness long before it strikes and so seek treatment far earlier than normal. Instead of relying on hi-tech hospitals, the emphasis (重点) is shifted to the home and easy-to-use gadgets. In the long run, the technology may even prevent illness by encouraging us to lead healthier lives.

Intelligent bandages are a good example. Powerful sensors within the bandage could quickly identify tiny amounts of bacteria in a wound and determine what medicine would work best. The cut could then be treated instantly.

The biggest development is melanoma(黑色素瘤) monitor designed to give early warnings of cancer. It could be used to take a picture of your body each week, and then compare it to previous images. If a problem is found, the system would advise you to get a check-up.

If all this sounds worrying, then help is at hand. Experts are also working on a "digital doctor", complete with a comforting bedside manner. A standard computer would be able to understand your voice and answer questions about your symptoms in plain English and in a way which could calm your nerves.

Stress is no sweat either. A portable communication aid could recognize certain phrases and tones and let you know when you are about to lose your temper. The software would also suggest ways of keeping your cool.

Researchers are still struggling, however, with making the technology cheap and simple enough for the household user. That is going to be the difficult part.