If something that you're doing doesn't challenge you, then it doesn't change you. We all need some normal stress in our lives, after all.{#blank#}1{#/blank#} So challenge the following limits:

    ⒈Figure out what you're scared of and do it continuously.

    If you're a salesman, and you're scared of talking to people personally or over the phone now, instead of being scared and thinking you'll fail, spend at least five minutes a day to pick up the phone and make a call. {#blank#}2{#/blank#} But don't stop on the first try! Eventually, you can look at fear in the eye and say, “Go on. I'm not scared!”

    ⒉{#blank#}3{#/blank#}

    Make sure this hobby is not linked to your career; you have to relax and relieve your stress while performing this. Some examples might be cooking, sewing, painting and so on. Apart from helping you challenge yourself, taking a class for your hobby may also give you extra income.

    ⒊Set aside at least nine minutes a day for physical exercise.

    {#blank#}4{#/blank#} A simple 9-minute run around your neighborhood can do wonders for yourself. Exercise can not only help you maintain your regular weight, but also make you feel better about yourself.

    ⒋Travel and allow yourself to be interested in new people.

Don't just limit yourself to your fellow travelers—-try to connect with the service staff. You never know what kind of people they're going to be. Get out of your house or go online right now to book your class. {#blank#}5{#/blank#}

A. You should do it continuously.

B. Someone may hang up on you.

C. You don't need to go to the gym.

D. Running in the gym may be a better choice.

E. Start to travel now and learn to challenge yourself.

F. Take a class for a hobby you've been wanting to develop.

G. You can never see any improvement if you stick to your comfort zone.

    Anyone watching the autumn sky knows that migrating birds fly in a V formation, but scientists have long debated why. A new study finds that these big－winged birds carefully position their wingtips and flap(拍动) at the same rate, probably to catch the upward movement of air and save energy during flight.

    There are two reasons birds might fly in a V formation: It may make flight easier, or they're simply following the leader. Squadrons(中 队) of planes can save fuel by flying in a V formation, and many scientists suspect that migrating birds do the same. Models that treated flapping birds like fixed－wing airplanes show that they probably save energy by drafting off each other, but currents created by airplanes are far more stable than those coming off of birds.

    Just as aerodynamic(气动力) calculations would predict, the birds positioned themselves to fly just behind and to the side of the bird in front, timing their wing flaps to catch the uplifting eddies(涡流). When a bird flew directly behind another, the timing of the flapping reversed(相反) so that it could minimize the effects of the downdraft coming off the back of the bird's body. “We didn't think this was possible,” Usherwood says, considering that the difficult achievement requires careful flight and incredible awareness of one's neighbors. “Perhaps these big V formation birds can be thought of quite like an airplane with wings that go up and down.”

    The findings likely apply to other long－winged birds, such as pelicans and geese, Usherwood says. Smaller birds create more complex wakes(尾波) that would make drafting too difficult. The researchers did not attempt to calculate the birds' energy savings because the necessary physiological measurements would be too invasive for an endangered species. Previous studies show that birds can use 20% to 30% less energy while flying in a V.

    Scientists do not know how the birds find that aerodynamic sweet spot, but they suspect that the animals line themselves up either by sight or by sensing air currents through their feathers. In future studies, the researchers will switch to more common birds, such as pigeons or geese. They plan to investigate how the animals decide who sets the course and the pace, and whether a mistake made by the leader can ripple through the rest of the flock to cause traffic jams.

    A study showed that the experiences children have in their first few years are important. These experiences affect the development of the brain. When children receive more attention, they often have higher IQs. Babies receive information when they see, hear and feel things, which makes connections between different parts of the brain. There are a hundred trillion(万亿)connections in the brain of a three-year-old child.

    Researcher Judit Gervain tested how good newborns are at distinguishing different sound patterns. Her researchers produced images of the brains of babies as they heard different sound patterns. For example, one order was mu-ba-ba. This is the pattern"A-B-B". Another order was mu-ba-ge. This is the pattern “A-B-C”. The images showed that the part of the brain responsible for speech was more active during the" A-B-B" pattern. This shows that babies can tell the difference between different patterns. They also were sensitive to where it occurred in the order.

    Gervain is excited by these findings because the order of sounds is the building block of words and grammar." Position is key to language," she says. "If something is at the beginning or at the end, it makes a big difference: John caught the bear.' is very different from 'The bear caught John.'”

    Researchers led by scientist Patricia Kuhl have found that language delivered by televisions, audio books, the Internet, or smartphones－no matter how educational－doesn't appear to be enough for children's brain development. They carried out a study of nine-month-old American babies. They expected the first group who'd watched videos in Chinese to show the same kind of learning as the second group who were brought face-to-face with the same sounds. Instead they found a huge difference. The babies in the second group were able to distinguish between similar Chinese sounds as well as native listeners. But the other babies－regardless of whether they had watched the video or listened to the audio－learned nothing.

The Coolest Inventions

    An Oceans Vacuum(吸尘器)

    There's a collection of plastic trash in the middle of the Pacific Ocean. It's bigger than Texas and growing. The way to clean it up now is to catch it with nets. That is both costly and slow. Instead, the Ocean Cleanup Project proposes a 62-mile-long floating barrier that would use natural currents to trap trash. If next year's trials succeed, a full cleanup operation would aim to start in 2020. It could reduce the trash by 42 % over 10 years.

    Easy-On Shoes

    In 2012, Matthew Walzer, a high school student with a disability, sent a note to Nike. "My dream is to go to college," he wrote, "without having to worry about someone coming to tie my shoes every day." Nike assigned a design team to the challenge. This year, they came out with their solution: the FlyEase. The basketball shoe can be fastened with one hand. A pair of Nike FlyEase shoes sells for $ 130.

    An Airport for Drones (无人机)

    As Amazon, Google, and others get ready for drone delivery service, there is one big question: What kinds of home bases will their drones have? Rwanda, in Africa, may have the answer. There, workers will soon start work on three "drone ports". The goal is to make it easier to transport food, medical supplies, electronics, and other goods through the hilly countryside. Construction is set to be completed in 2020.

How to write an email?

    While many people are accessible by email, sometimes it is difficult to determine how exactly to write an email to them. Here are some tips for you to follow.

    Write an appropriate subject line. The subject line should tell the recipient (接收者) immediately what the email is about. {#blank#}1{#/blank#} Remember that your wording also has to be brief.

    {#blank#}2{#/blank#} It is best to be more formal rather than informal, so when writing to someone you have never met or written to before, a "Dear Jane Smith" is appropriate. When addressing someone whom you are a little familiar with, a "Dr. Smith" is okay until they tell you to address them by their first name, in which case a simple "Jane" will be okay.

    {#blank#}3{#/blank#} Within the first two sentences of your email, your recipient should know exactly why you are writing to him. Sometimes an introduction may have to precede (先于) the sentence that states why you are writing, and sometimes it has to follow.

    Use appropriate language. You may be used to using informal language in certain social settings. {#blank#}4{#/blank#} Even when dealing with colleagues or friends you are familiar with, do not immediately fall back on informal language.

    Keep it simple. People may get dozens and even hundreds of emails a day. {#blank#}5{#/blank#} In that way, they can save much of their time when reading emails.

A. Use proper greetings.

B. Express your ideas clearly.

C. State your purpose at the beginning.

D. Be as specific as possible when writing the subject.

E. However, an email may not be the best place to use such language.

F. It is important to check the language to avoid spelling and grammar mistakes.

G. It is always easier for them if you keep your email as short and brief as possible.

    "What kind of rubbish are you?" This question might normally cause anger, but in Shanghai it has aroused complaints over the past week. On July 1st the city introduced strict rubbish-sorting regulations as a model for the country. Residents must divide their waste into four separate categories and throw it into specific public bins. They must do so at scheduled times, when monitors are present to ask the nature of one's rubbish, otherwise, they will face fines or worse.

    Shanghai authorities are responding to an obvious environmental problem. It generates 9 million tonnes of garbage a year, more than London's annual output and rises quickly. But like other cities in China, it lacks a recycling system. Individuals who fail to recycle could be fined up to 200 yuan (＄29). For repeat, the city can add black marks to their credit records, making it harder for them to obtain bank loans or even buy train tickets.

    Some object to this. Peng Feng of the Shanghai Academy of Social Sciences warns that the use of the credit system is overkill, raising a risk that officials will abuse their power. But others say a tough campaign is necessary. "Slowly people will get used to it," says Li Changjun of Fudan University.

    Many residents support recycling but are frustrated by the details. Rubbish must be divided according to whether it is food, recyclable, dry or harmful, the distinctions among which can be confusing, though there are apps to help work it out. Some have complained about the rules surrounding food waste. They must put it straight in the requisite public bin, forcing them to tear open plastic bags and toss (撕开) it by hand. Most upsetting are the short windows for throwing rubbish, typically a couple of hours, morning and evening. Along with the monitors at the bins, this means that people go at around the same time and can keep an eye on what is being thrown out; no one wants to look bad.