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.”

    The tallest building in the United States, the One World Trade Center, opened on November 3, 2014 in New York. The building is 1,776 feet tall, making it the 3rd tallest building in the world. It has 104 floors. The building stands in the area where the twin towers of the World Trade Center once stood. On September 11, 2001, a group of terrorists destroyed these twin towers and killed nearly 3,000 people. It took 8 years to build the new One World Trade Center. Does the height of the building in feet reminds you of something in history? The number is the year when the United States declared(宣布) its independence(独立) from Great Britain.

    One problem with such a tall building is how to clean the windows. Well, a platform(平台) hangs from ropes, and workers on the platform clean windows. On November 12, while two men were busy cleaning windows, a rope of the platform broke near the 68th floor. The two men were saved by cutting a hole in the glass window.

The two tallest buildings in the world are the BurjKhalifa in Dubai, UAE and the Makkah Royal Clock Tower in Mecca, Saudi Arabia.

    The month of March was a milestone for supporters of renewable energy in the U.S. For the first time, wind and solar power accounted for more than 10% of the country's electricity—up from less than 1% at the turn of the century. And total wind and solar power-plant capacity(发电量) is expected to grow more than 30% over the course of this year and next, according to the Energy Information Administration.

    Such forecasts have led many scientists and policymakers to think that moving a large part of the nation's power supply to renewable sources—as cities from Miami Beach to Salt Lake City have promised to do—may not be as far-fetched as once thought. But like any debate, there are dissenters, including those inside the federal government. Their argument is that the nation demands an uninterrupted supply of electricity and cannot count on sun, wind and natural gas to provide it. “You need solid hydrocarbons(固体碳氢化合物) on-site for rising peak demand,” Environmental Protection Agency administrator Scott Pruitt said on Fox Business in May, referring to the importance of coal as a power source.

    Many experts say the government's concern fails to account for how the power grid(电网) has improved in recent decades. Utility companies(公共事业公司) have developed innovative ways to move electricity from place to place to account for variation in weather. Battery technology can store power for use when renewable sources cannot operate, meaning solar power can be used on days when the sun doesn't shine. And the nation's vast supply of natural gas can be turned into usable energy with the flick of a switch.

    “I don't think 5 or 10 years ago I'd be comfortable telling you we could not sacrifice reliability when we're going to have 35% of our energy come from wind,” said Ben Fowke, CEO of the utility company Xcel Energy, at a recent conference. “I'm telling you, I'm very comfortable with that today.”

    Indeed, many parts of the country are already close to that reality. In some regions, like Iowa and Kansas, renewable energy supplies more than 25% of the electricity. The market has shifted so far in favor of natural gas and renewable energy that even the most concerted federal effort is unlikely to stop its growth. Any attempt to slow the growth of wind and solar will face strong pushback. “If anyone wants to do away with it,” Republican Senator Chuck Grassley told Yahoo News of the federal government's potential cuts to wind energy, “he'll do it over my dead body.”

    But the federal government could slow the acceleration—and with billions of dollars in private and public investments at risk, the pace of change matters. Decisions made today will shape the future of the nation's energy grid for decades to come.

    Charity is simple in theory：A heart warms, a hand reaches out. In practice, though, charity can become a troubled mix of motives and consequences. Giving can be driven by guilt, duty, praise, or perhaps the hope that giving will somehow make up for past cruelty or ignorance. Too little charity is far less than valuable. Too much can cause dependence which makes the receiver continuously ask for more.

    Giving from the heart is good. But critics have long worried about misdirected charity that does more harm than good. In his 2012 book, "Harmful Charity: How Churches and Charities Hurt Those They Help（And How to Solve the Problem）, "Robert Lupton, an experienced social worker of 40 years of community work in inner-city Atlanta, argues that charity must not do for the poor what they can do for themselves.

    Due to emergencies such as natural disasters, the afterward financial aid is greatly welcome. Mr. Lupton advocates it should focus on the development of self-supporting. The task can be carried out via, for instance, offering microloans, hiring local builders and suppliers, and trying to found self-supported, locally owned and operated enterprises. What seldom works, he argues, are untargeted handouts from far-off providers and the sudden arrival of inexperienced volunteer-tourists hoping to earn personal reputation by digging wells or mending roofs that locals are perfectly able to take care of themselves.

    Getting charity right isn't easy. But from money raising to the boom in volunteering among Millennials（千禧一代）, from the increasing worldwide willingness to give to the efforts by charity organizations to become more effective and fruitful, there is strong evidence that human beings' ability of taking care of others is growing along with their ability to help without harming.

    Charity can be as simple as holding the door for a stranger and as complex as a global campaign to get rid of malaria（疟疾）.Charity works best when it returns the weak to strength, when it helps a small town shaken by a heavy earthquake get back on its feet. A successful charity is one that eventually is no longer needed.

    Have you ever been into a cave? If not, please follow us and explore some of the most beautiful caves from around the world!

    Marble Caves

    Located in the center of Lake General Carrera, the Marble Caves in Chico, Chile, are only accessible by boat. The surrounding crystal clear waters allow visitors to see the rock formations beneath them while the rock ceilings above change color(depending on the writer levels and the season). The best time to visit: during sunrise and sunset, when the sun's rays light up the cave walls, making it an experience to remember.

    Reed Flute Cave

    Reed F1ute Cave known as "the Palace of Natural Arts" is located in the northwest of Guilin in southern China. The limestone cave offers a grand fairyland of stalactites(钟乳石), stone pillars, stone curtains, birds, plants and animals in fantastic shapes and colors.

    Fingal's Cave

    This incredible sea cave is located on the uninhabited island of Staffa in Scotland. The cave's size, shape, and naturally­arched(拱形的) roof combine with the waves to create strange sounds that enhance its cathedral­like atmosphere.

    The Blue Grotto

    The Blue Grotto is the symbol of Capri. It is a sea cave found on the coast of the island and is a well-known spot to all who visit the area. This cave is unique for its brilliant blue light which comes from two sources: the entrance to the cave and a bigger hole beneath the entrance. When viewed from inside the cave, the entrance appears as a brilliant white light just above the waterline, while the underwater hole, which is the larger source of light, provides a blue light.

    Happy, angry, amazed—these are some of the emotions we like to express these days when we're sending a message on our smart phones! That's why many of us now add little pictures to our texts to brighten up someone's mobile screen but we're also using them as a quick way of telling someone how we're feeling. Yes, emojis (表情符号) have become a popular tool for communication.

    The emoji was first invented in Japan in the late 1990s and the word "emoji" comes from the Japanese words for "picture" and "character". The number of different images has greatly increased since then and now we have a picture for nearly every mood or situation.

    Why are emojis widely used today? Professor Vyv Evans says, "Increasingly, what we're finding is that digital communication is replacing face-to-face talk in some ways. One of the reasons why emojis are so interesting is that they really do enable us to express our emotional selves much more effectively."

    Another advantage of emojis is that they are an international language—they don't use words but tell a message with pictures so they can be easily understood whatever your native language is.

    But as linguist (语言学家) Neil Cohn says, "To many, emojis are an exciting evolution (进化) of the way we communicate; but to others, they are linguistic Armageddon." It does show by using emojis, there is a lot more to our communication than words alone, but does this also mean that the traditional writing will die out one day?