Sunscreens (防晒霜) can offer protection from two types of ultraviolet (UV) rays (紫外线): UVB, which according to the Skin Cancer Foundation, are the chief cause of sunburn and play a key role in the development of skin cancer, and UVA, which get through the skin more deeply and are largely responsible for skin aging and wrinkling, as well as skin cancer risk. The SPF (防晒指数) measurement on sunscreens refers to the UVB protection level — and the number may not mean what you think it does. SPF 15 doesn't protect you from 15% of UVB rays, just as SPF 100 doesn't protect you from 100% of the rays. In fact, as you get into the higher numbered SPF sunscreens (think: 50 and above), the difference in UVB protection is actually pretty small.

    Theoretically, though the increase in UVB protection with a super-high SPF sunscreen may be not worth considering, it may help, and certainly can't hurt, to use it — that is, as long as you do so correctly. “The only downside is whether you're giving yourself a sense of false security,” Dr. Gohara says.

    Indeed, as Dr. Wang also pointed out, when people choose increased SPFs, they may actually feel so protected by the product that they finally ignore proper sun protection. “When people use really high SPF products, they tend not to reuse, they tend to stay out in the sun much longer, and they don't use other protective measures such as clothing and hats,” he says. Regardless of any increase in protection that a high SPF may or may not offer, one thing is certain: It doesn't give your body a free pass from sunburns, aging, or cancers, and it doesn't protect you from those things for any greater length of time than the lower SPF options. Both Dr. Wang and Dr. Gohara emphasized that, no matter what the SPF is, it's important to reapply your sunscreen every two hours.

    There's a whole lot of things that people fill their stomachs with. Some of them keep people alive. Some of them taste good to people. Some of them help people win pie-eating contests. Alcohol does none of these things. Why do people keep drinking it? And what does it do once it gets to their stomachs?

    There are all kinds of alcohol molecules (分子), but the one that people most often pour down their throat is ethanol (乙醇). Ethanol is very tiny and it dissolves in water, so it gets into all sorts of places that it's not supposed to. Alcohol heads for the digestive system. Because it dissolves in water, it can get into the water in the bloodstream. Because ethanol, to a certain extent, can pass through cell membranes(膜). It can go almost anywhere. It spreads through the muscles, and is sweated（出汗） — unmetabolized(未经新陈代谢的) and whole — through the skin. It gets into the heart. It even takes a walk through the brain, and this is the secret of its powers.

    Alcohol depresses the nerves, and the nerves affect almost every area of the body. Enough alcohol makes people sleep, so people who become unconscious choke on their own vomit (呕吐物). Most worryingly, enough alcohol can shut down those parts of the brain just like any other parts. People become unconscious and their brains simply forget to breathe.

    Alcohol is broken down in the liver. Alcohol doesn't destroy the liver, but products that the liver breaks the alcohol into do cause damage. A glass of wine per day can not do any harm. Instead, it can prevent heart attacks or can make someone functionally young. And it is kind of nice to know that sometimes, relaxation and cheer can be bottled. All that's needed is to take care how much alcohol is let into a person's brain.

    Feeling sad is an important part of human nature.

    Jerome Wakefield, a professor at New York University, mentions that feeling down after your heart is broken is normal and may even be beneficial. Recently, Wakefield's students have been coming up to him because their parents are pressuring them to get help for their sadness; often the kids want no part of it. Rather than “listen to medicine,” they want to listen to their hearts. He believes these students' reaction represents an important part of human nature.

    Professor Diener, who has studied happiness for a quarter century, finds that the Scots and many other peoples like being sad, and don't appreciate being told they should be happier. “They say too much happiness might not be such a good thing, no matter where it comes from,” says Diener. He believes it's wrong for the “happiness industry” to send the message that not only can we all be happier, but we have a duty to be so. He argues that what is considered normal sadness is something we shouldn't avoid.

    Eric Wilson, a professor at Wake Forest University, made every effort to smooth out his habitual frown and wear a sunny smile, since a happy expression can lead to happy feelings. He even tried to be enthusiastic. When neither of these made him happy, he concluded that such a happiness movement was no good for him at all. Americans, love for happiness, he writes, creates an environment where sadness is not valued.

    These researchers believe the problem of continuous, extreme happiness should not be surprising, since negative emotions developed for a reason. Fear warns us against the presence of danger, for instance. Sadness, too, seems to be part of our DNA: monkeys, dogs and elephants all display something that looks like sadness. Being “up” all the time can cause you to play down very real threats.

    They believe that only by experiencing sadness can we experience the fullness of the human condition. Their studies show that when you are in a negative frame of mind, you become more logical and more creative. Abraham Lincoln was not limited by his dark moods, and Beethoven composed his later works in a sad state. Vincent van Gogh, Emily Dickinson and other artistic giants saw the world through a glass darkly.

    People who are somewhat unhappy are more motivated to improve both their own lot and the lot of their community. In contrast, people at the top of the happiness charts feel no such urgency. “If you're totally satisfied with your life,” says Diener, “you don't feel like working for change. Be careful when people tell you that you should be happier.”

    One day, when I was working as a psychologist（心理学家）in England, an adolescent boy showed up in my office. It was David. He kept walking up and down restlessly, his face pale, and his hands shaking slightly. His head teacher had referred him to me. “This boy has lost his family,” he wrote. “He is understandably very sad and refuses to talk to others, and I'm very worried about him. Can you help?”

    I looked at David and showed him to a chair. How could I help him? There are problems psychology doesn't have the answer to, and which no words can describe. Sometimes the best thing one can do is to listen openly and sympathetically（同情）

The first two times we met, David didn't say a word. He sat there, only looking up to look at the children's drawings on the wall behind me. I suggested we play a game of chess. He nodded. After that he played chess with me every Wednesday afternoon—in complete silence and without looking at me. It's not easy to cheat in chess, but I admit I made sure David won once or twice.

    Usually, he arrived earlier than agreed, took the chess board and pieces from the shelf and began setting them up before I even got a chance to sit down. It seemed as if he enjoyed my company（陪伴）. But why did he never look at me?

    “Perhaps he simply needs someone to share his pain with,” I thought. “Perhaps he senses that I respect his suffering.” Some months later, when we were playing chess, he looked up at me suddenly.

    “It's your turn,” he said.

    After that day, David started talking. He got friends in school and joined a bicycle club. He wrote to me a few times, about his biking with some friends, and about his plan to get into university. Now he had really started to live his own life.

Maybe I gave David something. But I also learned that one…without any words—can reach out to another person. All it takes is a hug, a shoulder to cry on, a friendly touch, and an ear that listens.

    In today's Internet age, the demand for online games continues to grow. Online computer game centers exist in many cities and towns throughout Asia. Facing the pressures of school and life, people tend to the virtual（虚拟的）world, expecting a diversion from these problems. Too often, however, they can lead to problems and unhealthy addictions.

    This is most clearly seen in the example of South Korea. The country has the world's highest percentage of high-speed Internet services. It also has a high number of online game players and related problems. In 2002, a young man collapsed(突然晕倒) and died while playing online games. He had been playing almost non-stop for 86 hours at an Internet café. Another young man killed his sister after becoming confused between the online world and real life. A 12-year-old boy stole US $ 16,000 from his father and ran away from home. He did this to continue his obsession(着迷) with an online game. Such problems, however, don't just happen in South Korea. They are spreading to other parts of Asia as well.

    What kinds of people develop online game addiction? What does the problem look like? Dr. SueHuei Chen, a clinical psychologist, researches Internet addiction. She discovered some signs of at-risk individuals such as lack friendships and good social skills. Those problem individuals feel it so compulsive（强迫的）to play online games that they could sacrifice things such as school or family. They feel the need to spend more and more time online. And they become upset if anyone tries to limit their online game playing.

    How many problem game players are there? In mainland China, the potential number of problem online gamers is alarming. In 2004, the China daily reported that China had 13.8 million online game players. Besides, it stated that 80 percent of these were under 25 and had signs of addiction. Such numbers point toward a growing problem among Chinese youth.

    Make sure to keep control over your online game playing. If you don't control it, it can get control of you.

    The love story between John F. Kennedy and his wife, Jackie, was far from perfect and was tragically cut short in 1963 by a sniper's(狙击手) bullet.

    On November 22, 1963, President John F. Kennedy was seated beside his smartly dressed wife, who was wearing a pink Chanel-like suit and matching pillbox hat and holding an armful of red roses that had been presented to her by fans. They were seated in the back seat of a dark blue 1961 Lincoln with John Connally, the Governor of Texas and his wife, Nellie.

    And then came the dark moment. As the motorcade(车队) passed the Texas School Book Depository on Elm Street, a loud noise—like the sound of a firecracker—cracked the air. President Kennedy slumped(耷拉) forward, Jackie putting her arms around him.

    The look on her husband's face after he was shot would haunt Jackie for the rest of her life. The last words she ever got to say to him were, "I love you, Jack. I love you," according to Anderson, although Jackie herself recalled it slightly differently in a 1963 interview. All the way to Parkland Hospital, where President Kennedy would eventually be pronounced dead, as she recalled it, she was bent over him, asking "Jack, Jack, can you hear me? I love you."

    Jack Kennedy's final words to his wife of 10 years were far more mundane, of course. He had no way of knowing what was about to happen. It's been reported that Jack's final words were, "My God, I've been hit," but physicians have said this was impossible given Jack's injuries. Well, historians have now clarified that the last words Jack spoke before the fatal shot were, "No, you certainly can't."

    No, you certainly can't?

    He was making small talk in the car. "You certainly can't say that the people of Dallas haven't given you a nice welcome," the Texas Governor's wife had just remarked to Jack, referring to the huge, adoring crowd. "No, you certainly can't," Jack replied, milliseconds before the bullet from Lee Harvey Oswald gun struck.

    John F. Kennedy never spoke another word after that fateful day, but many things he said during his lifetime are incredibly inspiring.