While sweet treats can be hard to resist, the World Health Organization(WHO) has set new guidelines for people around the world. The guidelines, released on Wednesday, advise that both adults and children cut back on their sugar intake(摄取量) to stay healthy.

    In a statement, Francesco Branca, director of the WHO's nutrition department, said there is evidence that reducing daily sugar intake reduces the risk of being overweight and tooth decay(腐烂).

    The guidelines do not apply to the sugars in fresh fruit and vegetables or those that are naturally present in milk. According to the WHO, there is no reported evidence of negative effects of consuming those sugars. Instead, the new guidelines focus on “added” or “free” sugars. These include sugars that are added to processed foods and drinks such as candy and soft drinks.

    Added sugars are sometimes described as “ hidden” sugars because they exist in foods we might not think of as sweets, such as honey and ketchup(番茄酱). Health experts advise that consumers look at ingredients on food packages to help make better-informed decisions.

    The WHO recommends that people in the United States, Europe and other Western societies should cut their average sugar intake by about two-thirds, or down to just 10% of their overall calories. For developing countries, where dental care is less advanced, the WHO recommends that sugar intake be reduced to 5%.

    Scientist Kieran Clarke, of the University of Oxford, notes that for those people who can't shake their love for sweets, getting more exercise is a good solution. “If you get enough exercise, you can eat almost anything,” she said “But it's very hard to avoid large amounts of sugar unless all you're eating is fruit and vegetables.”

    Having a great collection of books at home doesn't really mean that you are a person who loves reading. It may be got from your father or your father's father, and it can just impress people around you with the fact that you are a person of culture.

    From my point of view, reading is very important in our daily life. For example, reading is a way of gaining knowledge in different areas. It can help us have a great imagination, and it makes things easier when it comes to making compositions on different themes. It gives you the possibility to speak about science, even if you don't work in this field. You can express your opinions about a political event because you have read something about that.

    Secondly, reading gives us the possibility to enter the world of imagination. We can imagine what life will be like in the future. Sometimes, we compare ourselves with the people in the stories we read and they can give us some clues to solve the problems and tell us what to do in certain situations. Books are based on real life. Even if writers are considered to be somehow different from common people, they often face the same problems as we all do.

    In short, I would like to say that literature is the perfect way of enriching our culture, expressing correctly, having a rich vocabulary, being able to understand different fields and really being considered to be a learned person.

    Certain activities can be good or bad for our brains, so let's see which of the seven habits you should carry on doing or give up.

Learn to cure cancer

    A vaccine for cancer is in the works.

    Lauren Landry and Chloe Tomblin are the scientists. They look in freezers(冰柜) for bacteria to use in the research. This research has its limitations—mostly because their lab is in a high school.

    But Lauren, 16, and Chloe,17 both students are Western Reserve Academy in the US, aren't put off by the difficulties they face in their cancer immunology(免疫学) class.

    “I hope we get to the point where we can get to a vaccine and write a paper,” Lauren said.

    Both conduct research into how to engage the immune system in stopping cancer from forming.

    Though the lab is in a high school, they don't use textbooks. The aim is to conduct real cancer research, either by testing the effects of substances on cancer cells or developing vaccines to target the growth of those harmful cells.

    The idea for the class came from Robert Aguilar, who has taught at the private school for many years. Students spend the first year learning research techniques. In the second year, students swap(调换) their blue lab coats for white ones. By this stage they are well into their research projects.

    “If first-years need any help, they can feel free to ask second-year students,” Aguilar said.

    Students form groups to conduct their research. One pair of students has researched the effect of capsaicin(辣椒素) on killing cancer cells. Another has tested the effect of caffeine(咖啡因) on the growth rate of breast cancer(乳腺癌) cells.

But few students get to the point in their research of experimentation with mice, Aguilar said. Lauren and Chloe hope that they can make decent progress in their work.

    “We know they're going to be used for good,” Lauren said. “If it does or doesn't work, it still has a huge impact.”

    Aguilar teaches the students that even research that doesn't work still contributes to science in some way. He tells students that “the best part of research is failing a lot”.

    An idea that started in Seattle's public library has spread throughout America and beyond. The concept is simple: help to build a sense of community in a city by getting everyone to read the same book at the same time.

    In addition to encouraging reading as a pursuit (追求) to be enjoyed by all, the program allows strangers to communicate by discussing the book on the bus, as well as promoting reading as an experience to be shared in families and schools. The idea came from Seattle librarian Nancy Pearl who launched (发起)the "If All of Seattle Read the Same Book" project in 1998. Her original program used author visits, study guides and book discussion groups to bring people together with a book, but the idea has since expanded to many other American cities, and even to Hong Kong.

    In Chicago, the mayor(市长)appeared on television to announce the choice of To Kill a Mockingbird as the first book in the "One Book, One Chicago" program. As a result, reading clubs and neighbourhood groups sprang up around the city. Across the US, stories emerged of parents and children reading to each other at night and strangers chatting away on the bus about plot and character.

    The only problem arose in New York, where local readers could not decide on one book to represent the huge and diverse population. This may show that the idea works best in medium-sized cities or large towns, where a greater sense of unity(一致)can be achieved. Or it may show that New Yorkers rather missed the point, putting all their energy and passion into the choice of the book rather than discussion about a book itself.

    Ultimately as Nancy points out, the level of success is not measured by how many people read a book, but by how many people are enriched by the process or have enjoyed speaking to someone with whom they would not otherwise have shared a word.

    One of my favorite hobbies is exchanging old-fashioned, paper-with-a-stamp-on-it postcards with random strangers around the world.

    The Postcrossing Project was created by Paulo Magalhaes in 2005. He liked getting mails—especially postcards. He thought others did, too—but how could he connect with them? That's when he came up with the idea of an online platform (postcrossing.com): There, postcard lovers like me can sign up to send a postcard to someone who has registered online, and receive a postcard in return.

    Along with a randomly selected address, participants get a unique code to put on the postcard. When the postcard arrives, the recipient registers that code with the site, which then causes the sender's address to be given to another postcrosser in turn. In practice, this means that for nearly every postcard I send (a few get lost in the mail) I get one back. And since I never know who will send me a card or where in the world they live, every trip to the mailbox holds the potential for a wonderful surprise.

    Privacy-conscious Americans might worry about sharing their address with strangers overseas. But postcrossers are friendly, polite, respectful folks—in more than 450 cards exchanged, I've yet to have a bad experience.

    On days when the international news is depressing, postcrossing is my comfort. There's nothing like getting a card from a child in China just learning to write in English, or a grandmother in Belarus describing her most recent gardening success to remind me that we truly are members of one global family, far more similar than we are different.

    It seems like such a small thing to send out a postcard. But as travel and communication technology continue to shrink the world, it's important to remember that it isn't just for diplomats and politicians to represent our country anymore. All of us have the power—and perhaps the responsibility—to be ambassadors, to show the best of your country to the world.

    And it's good to know that what you need to accomplish this is not necessarily complicated or expensive. It can be as simple as a postcard.