The universe looks like a pretty quiet place to live. But the universe is filled with dangerous things, all struggling to be the one to wipe us off the planet. Happily for us, they're all pretty unlikely, but if you wait long enough, one of them is certain to get us. But which one?

1). Death by Asteroid (小行星)

    Of all the ways we might meet our untimely death, getting wiped out by an asteroid is the most likely. Why? Because we sit in a universal shooting gallery, with 100 tons of material hitting us every day. The problem, though, occurs every few centuries when something big this way comes. If you could ask a dinosaur, I'd imagine they would tell you to take this seriously.

2). Death by Exploding Star

    When a huge star ends its life, it does so with a bang, which sends death spreading across space in the form of high-energy radiation. Many studies show that the bang would have to be closer than about 75 light years to do us any harm. The good news: no stars so close are able to do the deed.

3). Death by Dying Sun

    The sun is important to us; without it, we'd freeze. But the sun is also middle-aged, already halfway to running out of fuel, expanding into a red giant, and cooking us to a fine crisp. Even long before then, it'll warm up enough to raise our average temperature and cause a runaway greenhouse effect, boiling our oceans. Happily, that's a long time from now.

4). Death by Black Hole

    Black holes are misunderstood. They don't wander the galaxy looking for tasty snacks in the form of planets and stars; they turn around the Milky Way just like the hundreds of billions of other stars do. But it's possible that one could wander too close to us. If it did, planetary paths would be disturbed, causing the Earth to drop into the sun or be thrown out into deep space.

    Given that it could be trillions of years or more before even that happens, we don't have to worry too much about black holes.

    My advice? Go outside, look up, enjoy the sun, the moon, and the stars. They may be there forever as far as any one of us is concerned...and forever is a long, long time.

    Exercise may help to safeguard the mind against depression(沮丧) through previously unknown effects on working muscles, according to a new study involving mice.

    Mental health experts have long been aware that even mild, repeated stress can contribute to the development of depression and other mood disorders in animals and people. Scientists have also known that exercise seems to cushion against depression. But precisely how exercise, a physical activity can reduce someone's risk for depression, a mood state, has been mysterious. So for the new study, researchers at the Karolinska Institute in Stockholm studied the brains and behavior of mice in a complicated and novel fashion.

    We can't ask mice if they are feeling cheerful or in low spirits. Instead, researchers have pictured certain behaviors that indicate depression in mice. If animals lose weight, stop seeking out a sugar solution when it's available — because, probably, they no longer experience normal pleasures — or give up trying to escape from the cold-water zone just freeze in place, they are categorized as depressed. And in the new experiment, after five weeks of frequent but low-level stress, such as being lightly shocked, mice displayed exactly those behaviors. They became depressed.

    The scientists could then have tested whether exercise blunts (延缓) the risk of developing depression after stress by having mice run first. But, frankly, from earlier research, they wanted to know how, so they bred pre-exercised mice. A wealth of earlier research by these scientists and others had shown that aerobic exercise, in both mice and people, increases the production within muscles of an enzyme (酶) called PGC-1alpha. The Karolinska scientists suspected（怀疑） that this enzyme somehow creates conditions within the body that protect the brain against depression. Then, the scientists exposed the animals, which without exercising, were in high levels of PGC-1alpha to five weeks of mild stress. The mice responded with slight symptoms of worry. But they did not develop depression. They continued to seek out sugar and fought to get out of the cold-water zone. Their high levels of PGC-1alpha appeared to make them depression-resistant（抵抗的）. Finally, to ensure that these findings are relevant to people, the researchers had a group of adult volunteers complete three weeks of frequent endurance training, consisting of 40 to 50 minutes of moderate cycling or jogging. The scientists conducted muscle biopsies (活体检查) before and after the program and found that by the end of the three weeks, the volunteers' muscle cells contained substantially more PGC-1alpha than at the study's start.

    The finding of these results, in the simplest terms, is that “you reduce the risk of getting depression when you exercise,” said Maria Lindskog, a researcher at the Karolinska Institute.

    Believe it or not, school uniforms are absolutely not only clothes for students. They stand for the culture or beauty appreciation standard of a country. Let's take a look at school uniforms in different nations.

    School Uniforms in England

    Style of English school uniforms is rather classic, simple and elegant. Boys wear conventional western-style clothes, regular leather shoes and must wear neckties. Girls also wear western-style clothes, regular leather shoes and must wear bow-ties. This classic clothing style unconsciously affects English students' temperament (气质) and also sense of beauty.

    School Uniforms in Korea

    Do you still remember the classic scenes in My Sassy Girl? If you've watched it, you will know how stylish Korean students' uniforms are. Boys wear nice white shirts and western-style trousers. Girls wear white shirts, lovely skirts of latest design and bow knots.

    School Uniforms in Malaysia

    Students in Malaysia obey rather strict rules. Girls' dresses must be long enough to cover the knees. Shirts must cover the elbows. Compared with Thai students, they are much more conservative.

    School Uniforms in Japan

    For students, school uniforms in Japan are not only symbols for schools, but also symbols for the current fashion trends, even affecting students when choosing a school. Japanese school uniforms for girls originate in sailor suits. So they are also called sailor suits or sailor uniforms. Cartoon elements are used on them. Japanese school uniforms for boys are classic dark-colored clothes with stand-up collars, similar to Chinese tunic suits.

    Traveling without a map in different countries, I find out about different ways of directions every time I ask “How can I get to the post office?”

    Foreign tourists are often puzzled in Japan because most streets there don't have name signs. In Japan, people use landmarks (地标) in their directions instead of street names. For example, the Japanese will say to travelers, “Go straight down to the corner. Turn left at the big hotel and go past a fruit market. The post office is across from the bus stop.”

    People in Los Angeles, the US, have no idea of distance on the map: they measure distance by time, not miles. “How far away is the post office?” you ask. “Oh,” they answer, “it's about five minutes from here.” You don't understand completely, “Yes, but how many miles away is it, please?” To this question you won't get an answer, because most probably they don't know it themselves.

    People in Greece sometimes do not even try to give directions because tourists seldom understand the Greek language. Instead, a Greek will often say, “Follow me.” Then he'll lead you through the streets of the city to the post office.

    Sometimes a person doesn't know the answer to your question. What happens in the situation? A New Yorker might say, “Sorry, I have no idea.” But in Yucatan, Mexico, no one answers “I don't know.” People there believe that “I don't” is impolite. They usually give an answer, but often a wrong one. So a tourist can get lost very easily in Yucatan! However, one thing will help you everywhere in the world. It's body language.

    A new study shows students who write notes by hand during lectures perform better on exams than those who use laptops.

    Students are increasingly using laptops for note-taking because of speed and legibility(清晰度).But the research has found laptop users are less able to remember and apply the concepts they have been taught.

    Researchers performed experiments that aimed to find out whether using a laptop increased the tendency to make notes "mindlessly" by taking down word for word what the professors said

    In the first experiment, students were given either a laptop or pen and paper .They listened to the same lectures and were told to use their usual note-taking skills. Thirty minutes after the talk, they were examined on their ability to remember facts and on how well they understood concepts.

    The researchers found that laptop users took twice as many notes as those who wrote by hand. However, the typists performed worse at remembering and applying the concepts. Both groups scored similarly when it came to memorizing facts.

    The researchers' report said, "While more notes are beneficial, if the notes are taken mindlessly, as is more likely the case on a laptop, the benefit disappears."

    In another experiment aimed at testing long-term memory, students took notes as before but were tested a week after the lecture. This time, the students who wrote notes by hand performed significantly better on the exam.

    These two experiments suggest that handwritten notes are not only better for immediate learning and understanding, but that they also lead to superior revision in the future.

Nobody likes an old idiot(傻子).Developing a sense of humor is part of becoming a mature,emotionally healthy individual.Laughter is good for the soul,which builds friendships and relieves stress.It serves as the glue for social situations and as an ice-breaker for sadness and boredom.If you've ever been told to "lighten up" or "chill out",you should save the blue attitude for serious situations and develop your sense of humor.

Forgive the accident.A sudden fall is humorous not because we like to see people fall,but because it surprises us.From a spilled water glass in a meeting to Aunt Rae's teeth coming off in the Thanksgiving Day,the embarrassment of accidents can be relieved by humor and a helping hand.After making sure that nobody is hurt,forgive accidents with a chuckle(咯咯地笑) rather than a scolding.

Look for the unexpected.The kid who used to look at you with his eyes closed during a test had the idea.Parents who serve green eggs and ham to their children on graduation day get the idea.Unexpected action lightens the atmosphere and relaxes people.

Learn to laugh with your kids.Most of what children say and do is funny.Help them learn that accidents are sometimes funny and sometimes occasions for joining in and helping another human being.By sharing laughs and attempting to explain humor,you develop your sense of humor,as well as help kids develop their own sense of humor.