For thousands of years comets have been a mystery to man. They travel across the sky very fast and have a bright “tail” of burning gas. The comet Tempel 1 has an orbit（轨道） far outside the orbit of the furthest planet in our solar system, Pluto. It has been there for 4.6 billion years, 133 million kilometers from Earth. Last week a little American spacecraft crashed into Tempel 1. The spacecraft had a camera and it took a photograph of the comet every minute before it finally crashed into its surface.

    The space mission to Tempel 1 cost $335 million and was called Deep Impact. The spacecraft was travelling at 37,000 kilometers per hour when it hit the comet and the crash completely destroyed the spacecraft. But before it hit the comet, the spacecraft took some amazing photographs. The last one was a close-up picture which the spacecraft took just 3 seconds before it crashed into the comet.

    “Right now we have lost one spacecraft,” said a delighted NASA engineer. Deep Impact was like a American Independence Day fireworks display. It took many years to plan and ended in an enormous explosion. 

    The spacecraft which crashed into the comet was made of copper and was the size of a washing machine. It was dropped from a mothership into the path of the comet and the mothership then photographed the cloud of ice, dust and organic chemicals that rose from the surface of the comet after the crash.

    The crash completely destroyed the spacecraft but nothing really happened to the comet: experts believe that the crash slowed the comet down by no more than 1/10,000 of a millimeter a second.The aim of the mission was to study for the first time the interior of a comet.

    The mothership was 480 km from the explosion and observed the crash and the explosion with instruments for 800 seconds. Seven satellites, including the Hubble space telescope, watched the moment of drama, and over the next day and night about 50 telescopes on Earth were watching the distant comet.

    How could we live without the Internet? That's not how most of us keep in touch with friends, research a cool place to visit, or find out the latest news.{#blank#}1{#/blank#}But when you're moving through the Internet, you need to stay safe.

No Talking to Strangers

    Since you were a little kid, your mom or dad has probably told you not to talk to strangers.

    {#blank#}2{#/blank#} It's easy to meet a stranger on the Internet. You might visit a chat room or get an email or a text message from someone you don't know.

    It can be fun to make new friends, but do not communicate with strangers you meet online.{#blank#}3{#/blank#}．Children have been tricked online by people who pretend to be something that they're not. Some children have found themselves in a dangerous situation when they agreed to meet the mysterious (神秘的) online “friend” in person.

    {#blank#}4{#/blank#}The email could be from a person or a company trying to sell you something, A grown-up should decide what's best to do, which may include changing your email address or telling the police.

Keep Your Privacy (隐私)

    Anybody who uses the Internet has been asked to sign in, log in, or create a personal profile (简介). Kids need to check with a parent or grown-up before doing so. Why?{#blank#}5{#/blank#}．

    Another way to keep your privacy is to choose a screen name or email account name that isn't your real name.

A. You can do all these things online.

B. The same goes for the online world.

C. Let your parents know if a stranger emails you.

D. This information could be used for reasons you wouldn't like.

E. Think carefully before you create an email address or screen name.

F. Don't talk to them, agree to phone them, or email them photos of yourself.

G. Don't ask the strangers too many questions for information.

Third-Culture Kids

    Did you grow up in one culture, your parents came from another, and you are now living in a totally different country? If so, then you are a third-culture kid!

    The term “third-culture kid” (or TCK) was coined in the 1960s by Dr. Ruth. She first came across this phenomenon when she researched North American children living in India. Caught between two cultures, they form their very own. {#blank#}1{#/blank#} About 90 percent of them have a university degree, while 40 percent pursue a postgraduate or doctor degree. They usually benefit from their intercultural experience, which helps them to grow into successful academics and professionals.

    {#blank#}2{#/blank#} In fact many hardships may arise from this phenomenon. A third-culture kid may not be able to adapt themselves completely to their new surroundings as expected. Instead, they may always remain an outsider in different host cultures. Max, for example, experienced this fundamental feeling of strangeness throughout his life as a third-culture kid.{#blank#}3{#/blank#} While this can be a way to create a network of friends all around the world, it can be difficult for a third-culture kid like Max to maintain close friendships and relationships.

    For a third-culture kid, it is often easier to move to a new foreign country than to return to their “home” country. After living in Australia and South Korea for many years, Louis finally returned to Turkey as a teenager. But she felt out of place when she returned to the country where she was born. {#blank#}4{#/blank#} She did not share the same values as her friends' even years after going back home.

    While a third-culture kid must let go of their identity as foreigner when he/she returns, the home country can prove to be more foreign than anything he/she came across before. The peer group they face does not match the idealized image children have of “home”.{#blank#}5{#/blank#}

    As a part of the growing “culture”, TCKs may find it a great challenge for them to feel at home in many places.

A. Yet being a third-culture kid is not always easy.

B. In general, they often reach excellent academic results.

C. This often makes it hard for them to form their own identity.

D. However, their parents can help them see the opportunities of a mobile lifestyle.

E. Their experience abroad helps them to gain a better understanding of cultural differences.

F. Unlike other teens of her age, she didn't know anything about current TV shows or fashion trends.

G. Additionally, making new friends and saying goodbye to old ones will at some point become routine for a third-culture kid.

    Being physically active three times a week reduces the odds of being depressed by about 16%, according to new UCL research carried out as part of the Public Health Research Centre.

    The study, published in JAMA Psychiatry, found a two-way relationship between depression and physical activity. People who increased their weekly activity were reported to have fewer depressive symptoms but those with more depressive symptoms were less active, particularly at younger ages.

    Researchers followed 11,135 people born in 1958 up until the age of 50, recording depressive symptoms and levels of physical activity at regular intervals in adulthood. They found that each additional activity period per week reduced odds of depression by 6%. In England 19% of men and 26% of women are currently classed as "inactive", and this study suggests that activity could significantly improve their mental as well as physical health.

    "Assuming the association is causal, physical activity has a protective effect against depression. If an adult between his twenties and forties who isn't physically active became active 3 times per week, he would reduce his risks of depression by about 16%," said Dr Snehal of the UCL Institute of Child Health, lead author of the study.

    Professor Mark，Director of the Public Health Research Centre, said: "Many people are already aware of the benefits of physical activity on their general health, but now we are seeing more evidence that suggests it also has a positive effect on a person's mental well-being. The latest research highlights just how important it is to ensure that people are working and living in environments that allow them to be both physically active and mentally healthy."

    Sleep deprivation(缺失)is an important hidden factor in lowering the achievement of school pupils, according to researchers carrying out international education tests.

    It is a particular problem in richer countries with sleep experts linking it to the use of mobile phones and computers in bedroom late at night. Sleep deprivation is such a serious problem that lessons have to be dragged down to a lower level to suit sleep-deprived learners, the study found. The international comparison, carried out by Boston College, found the United States to have the highest number of sleep-deprived students, with 73% of 9- and 10-year-olds and 80% of 13- and 14-year-olds identified by their teachers as being negatively affected.

    In literacy(读写能力) tests there were 76% of 9- and 10-year-olds lacking sleep. This was much higher than the international average of 47% of primary pupils needing more sleep and 57% among the secondary age group.

    Other countries with the most sleep-deprived youngsters were New Zealand, Saudi Arabia, Australia, England, Ireland and France. High-performing Finland is also among the most lacking in sleep. Countries with the best records for getting enough sleep include Azerbaijan, Kazakhstan, Portugal, the Czech Republic, Japan and Malta.

The analysis was part of the huge date-gathering process for global education rankings, the Trends in International Mathematics and Science Study(TIMSS)and Progress in International Reading Literacy Study(PIRLS)

    “I think we underestimate the impact of sleep. Our data show that across countries internationally, on average, children who have more sleep achieve higher in maths, science and reading. That is exactly what our data show,” says Chad Minnich of the TIMSS and PIRLS International Study Center.

    “It's the same link for children who are lacking basic nutrition,” says Mr Minnich, based at the Lynch School of Education, Boston College. “If you are unable to concentrate, to attend mentally, you are unable to achieve at your best level, because your mind and body are in need of something more basic. Sleep is a fundamental need for all children. If teachers report such large proportions of children suffering from lack of sleep, it's having a significant impact. But worse than that, teachers are having to adjust their instruction based on those children who are suffering from a lack of sleep. The children who are suffering from a lack of sleep are driving down instruction.”

    That means that even the children who are getting enough sleep are still suffering from this sleep-related lowering.

Is your glass of milk half-full or half-empty? This saying is often used to test people's outlook in a situation; do they focus on the positives (a half-full glass) or the negatives (a half-empty one)? Thinking positively, with a belief that most things will turn out fine, is called optimism and it's known to boost your well-being. {#blank#}1{#/blank#}

Why is thinking positively good for you?

Research shows that people who are optimistic and think positively tend to experience less stress and cope well when faced with life's challenges. People who are more pessimistic (expect that the worst will happen) may find it hard to believe that these challenges will pass. Scientists have even found that thinking positively can make you live longer. {#blank#}2{#/blank#} This is because you believe your goals are achievable and within reach, which encourages you to work towards them.

{#blank#}3{#/blank#}

Everybody can worry from time to time. Worrying can help to keep you safe. If you were never worried and were greatly positive about how things would turnout, you wouldn't recognize risks. "Worrying is our brain warning us that there might be something threatening, which functions as a fire alarm." says child psychotherapist (心理治疗师) Rachel. "The trouble is that sometimes it goes off when there isn't a huge danger to face." {#blank#}4{#/blank#}

You should learn to think positively.

Optimism is shaped by your genes, which carry characteristics obtained from your parents, and by what happens to you. {#blank#}5{#/blank#} Research has shown that it can help to draw or write an outcome that's positive, like an image of you playing guitar and having passed your next grade. Imagining this can motivate you to work to achieve it, such as practising everyday afterschool.

A. Worrying is like a fire alarm.

B. Avoid worrying is beneficial to our health.

C. Asking others for help positively makes sense.

D. The good news is that everybody can learn to think more positively.

E. When this happens, you can feel anxious and hopeless about what lies ahead.

F. However, whatever your starting point is, you can learn to be more optimistic.

G. Being positive about the future goals can make you happier and more successful.