One of my first memories as a child in the 1950s was a discussion I had with my brother in our tiny bedroom in the family house in Bethlehem, Pennsylvania.

    We had heard in school about a planet called Pluto. It was the farthest, coldest, and darkest thing a child could imagine. We guessed how long it would take to die if we stood on the surface of such a frozen place wearing only the clothes we had on. We tried to figure out how much colder Pluto was than Antarctica, or than the coldest day we had ever experienced in Pennsylvania.

    Pluto, which famously was downgraded from a “major planet” to a “dwarf planet”(矮星) in 2006, captured our imagination because it was a mystery that could complete our picture of what it was like at the most remote corners of our solar system

    Pluto's underdog discovery story is part of what makes it so attractive. Clyde Tombaugh was a Kansas farm boy who built telescopes out of spare auto parts, old farm equipment and self-ground lenses. As an assistant at Lowell Observatory in Flagstaff, Arizona, Tombaugh's task was to search millions of stars for a moving point of light, a planet that the observatory's founder thought existed beyond the orbit of Neptune. On February 18, 1930, Tombaugh found it. Pluto was the first planet discovered by an American, and represented a moment of light in the midst of the Great Depression's dark encroachment(入侵).

    Pluto is much more than something that is not a planet. It's a reminder that there are many worlds out there beyond our own and that the sky isn't the limit at all. We don't know what kinds of fantastic variations on a theme nature is capable of making until we get there to look.

Dear Reader,

    Today I am going to ask you to support Wikipedia with a donation.

    Wikipedia is built differently from almost every other top 50 websites. We have a small number of paid staff，just twenty­three. Wikipedia content is free to use by anyone for any purpose. Our annual expenses are less than six million dollars. Wikipedia is run by the non­profit Wikimedia Foundation, which I founded in 2003.

    Wikipedia is driven by a global community of more than 150,000 volunteers — all devoted to sharing knowledge freely. Over almost eight years, these volunteers have contributed more than 11 million articles in 265 languages. More than 275 million people come to our website every month to access information,free of charge and free of advertising.

    But Wikipedia is more than a website. We share a common cause: Imagine a world in which every single person on the planet is given free access to the sum of all human knowledge. That's our commitment.

    Your donation helps us in several ways. Most importantly, you will help us cover the increasing cost of managing global traffic to one of the most popular websites on the Internet. Funds also help us improve the software that runs Wikipedia — making it easier to search, easier to read, and easier to write for. We are committed to increasing the free knowledge movement worldwide, by taking on new volunteers, and building strategic partnerships with institutions of culture and learning.

    Wikipedia is different. It's the largest encyclopedia (百科全书) in history, written by volunteers. Like a national park or a school, we don't believe advertising should have a place in Wikipedia. We want to keep it free and strong, but we need the support of thousands of people like you.

    Thank you,

Jimmy Wales

    Most dictionaries will tell you a number of things about a language. There are three important things. These three things are spelling, pronunciation(发音) and meaning.

    First, a dictionary will tell you the spelling of a word. If you are not sure about the spelling of a word, you can try to find the correct spelling in a dictionary. Words are listed in an alphabetical (字母表的) order —— a, b, c and so on. For example, on a dictionary page the "poor" comes before "poverty" and the word "poverty" comes before the "power".

    The words are always given in alphabetical order. The second thing, a dictionary will tell you the pronunciation. Most dictionaries give phonetic, or sound alphabet. The phonetic alphabet (音标) shows pronunciation. The third thing, a dictionary will tell you the meaning of words. You can look up a word and find out what it means. Many words have more than one meaning, and a good dictionary will tell you all of the word's meanings. For example, in English the common word "get" has over 20 different meanings.

    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."

    There are many weird sports that are present from around the world. From each region of the world, along with the very popular common sports, there are also those really popular but very weird kinds of sports.

    The Ultimate Test between Man and Horse:

    This indeed a very strange kind of sport that tests your stamina. You will learn how to be agiler while competing against a horse. This game originated in Welsh town of Llanwrtyd Wells. This sport really has to do with strength. You will require great agility and strength in order to take part in this. Marathon human contestants are put to test against those mounted on horses. This is how the marathon testing takes place.

    Love Locked Race

    This is a sports event that was first introduced in Finland. This is all about a male competitor racing with a female in a certain way. There would be many obstructions and blocks on the way which would definitely bring you challenges. The person to win would have to finish the race without losing his female partner in the course of overcoming the obstacles even for once. This race takes place really fast and the obstacles are set that way.

    Toe sport

    This is yet another weird sport that welcomes you to use your toes. This is quite the same kind of sport that you used to play as a child which involved toe wrestling. This has now been turned into a major sport that even has a World Toe Wrestling Competition. It first originated in a pub of Derbyshire.

    The locals took this sport with great enjoyment and then made this so popular that it soon had its own championship. The individuals who participate have only got to use their feet in locks but then this is tougher than it may sound.

    The Mud Pit Belly Flop

    This is a kind of game where even the spectators get splashed in mud but in fact that is quite the fun. The very annual Summer Redneck Games in East Dublin brings about this game and brings about some of the greatest hubcap discus throws with it. This is also a great sport to show the strength and dexterity of your feet.

Quantum mechanics (量子力学) is a branch of science that studies the smallest particles (粒子) in the universe, like atoms (原子) and even smaller things. It might sound super complex, but let's break it down in simple language.

Imagine you have a small particle, like an atom. In the world of quantum mechanics, these particles don't behave like the things we see in our everyday lives, like balls or cars. Instead, they act kind of like waves and particles at the same time, which is really strange!

One of the most famous ideas in quantum mechanics is the "Uncertainty Principle", raised by physicist Wemer Heisenberg. This principle says that we can't precisely know both the position and the speed of particle at the same time. It's not because our measuring tools are bad; it's because the particles themselves are naturally uncertain.

Another weird thing about quantum mechanics is something called "Entanglement". Imagine you have two particles that are connected in a special way. If you change one of them, the other instantly changes, no matter how far apart they are. It's like they're talking to each other faster than the speed of light, which goes against what we know from everyday experiences.

Quantum mechanics also deals with probabilities. Instead of saying, "This particle will be here at this exact time," scientists say, "There's a certain chance it'll be here, and a certain chance it won't." It's like predicting the weather, but on a super small scale.

In a nutshell, quantum mechanics is a strange and fascinating world where particles act both like waves and particles, where you can't know everything about a particle at once, and where particles can be mysteriously connected no matter how far apart they are. It's a mind-boggling field that challenges our understanding of how the universe works, and even though it's tough to grasp, it's an essential part of modern physics.