Best friends may be priceless but the cost of keeping the relationship alive is £23,870.

    According to a study, a BFF (best friends forever) does not come cheap with devoted friends spending £4,679 on birthday presents alone over a lifetime. And while it costs nothing to be a shoulder to cry on, big-hearted Britons go the extra mile and spend £168 on pick-me-ups(提神物品) to get their mate through a rocky patch (艰难时刻)like the breakup of a relationship.

    There's a further £242 spent on presents to show how much they mean from gifts bought on holiday to treats for no reason. And distance does not break up a close friendship as BFFs spend a whopping(巨大的) £18,000 on travel to see each other despite being miles apart because of university, jobs and marriage.

    The study by cashback site TopCashBack found on average BEFs who marry can expect £431 spent on them and a further £283 on gifts when they have children. And they can rely on their pals to help out when they move houses as they will obtain £127 worth of housewarming presents and takeaways(a kind of food).

    The survey based on a friendship lasting 40 years found more than eight in ten adults with a BFF felt their friendships were worth every penny.

    TopCashback spokesperson Natasha Smith said: “Those friendships which stand the test of time are often the most important in our lives. However, they come at a cost. From train tickets once a month to flights and a new dress for a wedding on the Italian coast, the price paid for having a best mate can soon add up. But when we asked people to compare their friendship with the financial investment(投资), only 14% thought their friendship was equal to their investment with the vast majority thinking it was worth more."

    Augusto Esquivel is a sculptor who, in his own words, is “crazy with comparisons of reality and potential and the balance between them.” Perhaps the best example of what he's talking about are his most famous creations: the suspended(悬挂的) button sculptures.

Made entirely from buttons hanging on various lengths of string, Esquivel's sculptures are made to look like common objects: a piano, a gumball machine, and even a toilet. If it wasn't for the clear string hanging above, these objects, these sculptures, would look solid, yet you can put your hands right through them. The process starts with him deciding on a subject and setting the acrylic （丙烯酸树脂）from where the buttons are being suspended. He buys buttons of different shapes and sizes, paints them with spray paint, and carefully hangs them. After that, it's a manner of hanging each individual button, which takes a lot of time. For his piano, for example, he individually hung over 60 pounds worth of tiny buttons.

Esquivel's sculptures, while mostly housed inside art galleries, perfectly capture one of the main principles of street art: something that is eye-catching and something that invites interaction. Often the best sculptures outside the art galleries aren't the ones behind guards and fencing, but the ones people can go right up to and touch. In Vancouver, a series of laughing old men are attracting people for pictures and to just generally hang around, but the people who simply walk by and see the sculptures almost always leave with a smile on their face. That's good street art: it draws the viewer in rather than relying on a gallery to draw in an audience and point them to certain pieces.

Esquivel's art is not only a presentation of talent, something that mentions larger philosophical questions, like the ones he stated above, but also just the right combination of interesting idea and painstaking work. One can look at his work in a critical way, or simply appreciate his idea and execution(艺术品的制作).

    We brush our teeth daily, but do you know everything you need to know about dental care and hygiene? Believe it or not, there is a lot more than most people realize. Luckily, here are several apps that can help you.

●Brush DJ

    You should brush your teeth for full two minutes as recommended by dentists, but that time can be difficult to judge. Many recommend you listen to music, because many songs are just around two minutes in length. Brush DJ has loads of great tunes that will get you into the two­minute habit. There are both songs to listen to, and videos to watch, and you'll find a variety of awesome tunes.

●Orasphere

    It's recommended that Orasphere videos be used by dentists for their patients, so they can learn about procedures. Those who do use these videos say that the software can greatly decrease the amount of time it takes to explain procedures to patients.

●American Dental Association(ADA)

    Everything you ever wanted to know about your teeth, and then some, can be found on the American Dental Association(ADA) website. You'll find loads of great articles that have the latest news about dentistry（牙科）. Those interested in dental careers will find plenty of information to head them in the right direction, and there's even a section devoted to public dental programs, including Give Kids a Smile and Fluoride in Water.

●DDS GP

    Here is more presentation software that explains all types of dental procedures. This is helpful for dentists to have, because they can better explain procedures to their patients.

●Dentistry IQ

    You can find information for dentists, hygienists, assistants, office managers, and more at Dentistry IQ. You can also get information about new products, clinical practices, and much more. In addition, you can learn about career opportunities, the most recent practices, and a whole lot more.

    When your dream is to become a footballer, nothing should get in your way—even if you have no feet.

    Gabriel Muniz, an 11-year-old Brazil kid, was born without feet. Although his family thought he would have serious difficulties living a normal life, he started walking before he was one year old. His mother would go after him, expecting him to keep falling, but he never fell. It took him a while to make the jump from walking to playing football, but he did make it. And, in fact, there's nothing he loves more than playing football. In his school, the skillful youngster (年轻人) is not only the best player in his school team but also the captain of his gym team.

    He knows that his disability means he'll never be able to play for a professional (专业的) football team. So Gabriel is hoping that football will one day become a Paralympics (残疾人奥运会的) sport. He proved to everyone there he could go head to head with any other boy. Watching him play is unbelievable. He's fast and he's got a big bag of tricks—he's very skilled and he does everything he can to copy his hero, Messi so much that he is invited to go to Spain to meet his hero Messi and show his talent in the Barcelona Football Club.

    His coach says he is proving the disability only exists (存在) inside our heads.

Swimming and English Learning

    Can you swim? Do you like swimming? Yes? Well, how can you learn to swim? I think the best way is to go into the water and learn. I'm afraid you'll never learn to swim just by reading books about swimming or looking at others swimming. It's the same with the English study. We must practice, practice and practice.

    Listening and speaking are very important for beginners. The children in English-speaking countries first listen to others. Then they try to imitate and speak. We can listen to English programs on radio. You may just understand a few words. It doesn't matter. Just be relaxed, try to catch every word.

    Somebody may be a good listener. But he dare not speak. He's afraid of making mistakes. You know we sometimes make mistakes when we speak Chinese. Don't be afraid. We must be brave. If you really want to learn English well, you must try to speak with everyone so long as he knows English. Whether you know him or not is not important when there's nobody to talk with, you can talk to yourself in English. It's interesting and also a good way to practice your spoken English. Remember, the more you speak, the fewer mistakes you'll make.

    Reading and writing are more important for senior school students. First we must choose the books we're interested in. A lot of reading will improve your language sense. This is the most important.

    Keep writing English diaries. We can also write English articles. You may even post them to English magazines. Don't be afraid of failure. Failure is the mother of success.

    Easier said than done. Well, let's do more practice from now on. I'm sure you'll learn English well in this way.

Researchers believe they have found evidence for a hidden ocean on Mimas, one of Saturn's major moons. This makes Mimas a target for learning more about the origins of life in our solar system. 

Saturn has 146 moons orbiting it. The biggest is larger than the planet Mercury; the smallest is roughly the size of a sports field on the Earth. Mimas, which was first discovered in 1789, is one of the major moons and is about 250 miles wide. 

Experts used to think Mimas was mostly made out of solid ice and rock. In 2014, astronomers noticed its orbit around Saturn was moving unsteadily. A shaky orbit can be caused either by a core shaped like a rugby ball or a huge liquid ocean beneath the surface. At first, lots of astronomers argued against the suggestion that Mimas had an ocean because there is no sign of it on the surface. 

To investigate more thoroughly, researchers looked at images taken by Cassini, a NASA spacecraft sent to study Satun. The images showed that the moon's orbit around Saturn drifted by about six miles over 13 years. The team's calculations found that the only way Mimas could move in this way is if it had a hidden ocean under the surface. They think the ocean formed when the moon's core warmed up and melted some of the ice. 

Mimas is just one of many moons that scientists think could have oceans below the surface Ganymede, which orbits Jupiter and is the largest moon in the solar system, has more water in its ocean than all of the oceans on the Earth. Titan, another of Saturn's moons, is believed to have a salty ocean beneath the surface. 

Space agencies want to study these oceans because they might be home to living organisms. However, the ocean on Mimas might not be old enough for life to have emerged there yet. It took hundreds of millions of years for life to develop on the Earth and the ocean on Mimas is relatively young;it is less than 25 million years old.