While serious training is important for all dogs, playtime is just as important.{#blank#}1{#/blank#} Use these games to help teach your dog how to play.

1）Hide and Seek

    Hide and seek isn't just for kids. Dogs can really enjoy this game. Pick up one of your dog's favorite toys or treats. Tell your dog to stay.{#blank#}2{#/blank#} When you are ready, call your dog to come to you. If possible, squeak(使吱吱叫)the toy or shake the treats. Reward your dog with praise and the toy/treat when she finds you.

2）Fetch

    Many dogs have a natural ability to fetch. Other dogs can be taught how.{#blank#}3{#/blank#}Play indoors with a soft toy or outdoors in a fenced-in area with a ball or disc. For dogs that really  love to run, try this game of fetch!

3）Find the Treat

    Dogs have superior senses of smell, and most love to use their noses to find food. Let your dog use her brain and her nose to find hidden goodies. First, have your dog stay out of sight. Then, hide her favorite treats in various places around the room.{#blank#}4{#/blank#} If help is needed, you can lead her around or point to areas for her to explore.

    Whatever the game, safety comes first! Remember to watch your dog for signs of exhaustion or overheating when you are playing. Stop if your dog seems tired or shows signs of anxiety. {#blank#}5{#/blank#}When other dogs or people are around, it may create a dangerous distraction(分神).

A. Then, go to find a good hiding place.

B. Try different games to see which your dog responds to best.

C. A good game of fetch can be played almost anywhere.

D. You can include games in training as well.

E. Also be aware of your surroundings when playing with your dog.

F. Encourage your dog to play with other dogs.

G. Bring your dog back in and tell her to “go find!”

    Being sociable looks like a good way to add years to your life. Relationships with family, friends, neighbors, even pets, will all help, but the biggest longevity (长寿) seems to come from marriage. The effect was first noticed in 1858 by William Farr, who wrote that widows and widowers (鳏夫) were at a much higher risk of dying than the married people. Studies since then suggest that marriage could add as much as seven years to a man's life and two to a woman's. The effect can be seen in all causes of death, whether illness, accident or self-harm.

    Even if the chances are all against you, marriage can more than compensate you. Linda Waite of the University of Chicago has found that a married older man with heart disease can expect to live nearly four years longer than an unmarried man with a healthy heart. Similarly, a married man who smokes more than a pack a day is likely to live as long as a divorced man who doesn't smoke. There's a flip side, however, as partners are more likely to become ill or die in the couple of years following their husband or wife's death, and caring for your husband or wife with mental disorder can leave you with some of the same severe problems. Even so, the chances favor marriage. In a 30-year study of more than 10,000 people, Nicholas Christakis of Harvard Medical School describes how all kinds of social networks have similar effects.

    So how does it work? The effects are complicated, affected by socio-economic factors, health-service provision, emotional support and other more physiological mechanisms(生理机制). For example, social contact can promote development of the brain and immune system, leading to better health and less chance of depression later in life. People in supportive relationships may handle stress better. Then there are the psychological benefits of a supportive partner.

    A life partner, children and good friends are all recommended if you aim to live to 100. The overall social network is still being mapped out, but Christakis says: "People are inter-connected, so their health is inter-connected."

    Brian Greene, a professor of physics and mathematics at Columbia University, has created an online science education platform. He tries to "build a bridge" with things you know about, and then "bring you across that bridge to the strange place of modern physics."

    Recently I had a chance to ask Greene about wormholes (a hole which some scientists think might exist, connecting parts of space and time that are not usually connected), time travel and other mysteries of the universe. I asked him a million-dollar question: What if I went through a wormhole and prevented my parents from meeting? "Most of us believe that the universe makes sense," Greene said. Although there are several interesting theories about time travel, he added, the laws of physics would probably prevent something so illogical from taking place. The good news is that the time paradox（悖论） is open for future physicists to solve.

    When asked how physics could become more exciting for kids, Greene said that books by Stephen Weinberg, Leonard Susskind, and other physicists, "make it a great time for people who want to learn about big ideas but aren't yet ready, perhaps, to learn math."

    When I pointed out that some students still might find physics boring, Greene said that the key is to teach them about things that are strange. "The basic stuff is important," Greene said. "But I think it's really important to also describe the more modern ideas, things like black holes and the Big Bang. If kids have those ideas in mind, then at least some of them will be excited to learn all the details．"

    Greene has followed Albert Einstein's lead in trying to solve the mysteries of the universe. Now he wants kids to do the same. As Greene said, physics is "not just a matter of solving problems in an exam." It's about experimenting, showing an interest in strange phenomena（现象）-- and having fun!

    After years of trying, our neighbors convinced my parents that ice fishing would be a fun winter getaway from our dairy farm. Before that, their idea of entertainment involved driving around the countryside to see how the neighbors' crops were doing.

My parents eventually built a fish house and set it up on Wood Lake. We excitedly headed for the lake on many January and February weekends. By the time we arrived at our favorite fishing spot across the lake each day, somebody had usually made a clear path across the ice. The fish houses were together at the best fishing spots, forming some kind of a neighborhood.

    Our house was large enough so all four of us could fish at the same time. Each corner had a square cut out of the floor. We sat in comfort. You'd think ice fishing would be cold, but we had a small woodstove (木炉) inside, and we put snow around the bottom of the house to keep the wind from blowing underneath.

    Besides the thrill of watching your bobber (钓鱼浮标) dip below the water, lunch was always the highlight of the day. Mom would fry pork or hamburgers in a pan. The smell of cooking meat was the envy of every other fish house in the neighborhood.

    Our days passed with a mix of quiet time and family chatter. We talked about the farm or school. And of course, we shared fishing advice. Part of the fun of ice fishing was learning to understand and trust the sounds of the frozen lake. Healthy ice "talks" as it freezes and shifts. You could often hear the sound of a crack traveling through the ice.

    People who have never tried ice fishing may not think it sounds very exciting, but it was for us. Fishing trips were an adventure. We didn't always catch fish, but we always brought home great memories of a day with family and friends.

    Ever walked to the shops only to find, once there, you've completely forgotten what you went for? Or struggled to remember the name of an old friend? For years we've accepted that a forgetful brain is as much a part of aging as wrinkles and gray hair. But now a new book suggests that we've got it all wrong.

    According to The Secret Life of the Grown-up Brain, by science writer Barbara Strauch, when it comes to the important things, our brains actually get better with age. In fact, she argues that some studies have found that our brain hits its peak between our 40s and 60s — much later than previously thought.

    Furthermore, rather than losing many brain cells as we age, we keep them, and even produce new ones well into middle age. For years it's been assumed that brain, much like the body, declines with age. But the longest, largest study into what happens to people as they age suggests otherwise.

    This continuing research has followed 6,000 people since 1956, testing them every seven years. It has found that on average, participants performed better on cognitive (认知的) tests in their 40s and 50s than they had done in their 20s. Specifically, older people did better on tests of vocabulary, verbal memory (how many words you can remember) and problem solving. Where they performed less well was number ability and perceptual speed — how fast you can push a button when ordered. However, with more complex tasks such as problem-solving and language, we are at our best at middle age and beyond. In short, researchers are now coming up with scientific proof that we do get wiser with age.

    Neuroscientists are also finding that we are happier with aging. A recent US study found older people were much better at controlling and balancing their emotions. It is thought that when we're younger we need to focus more on the negative aspects of life in order to learn about the possible dangers in the world, but as we get older we've learned our lessons and are aware that we have less time left in life: therefore, it becomes more important for us to be happy.

Beethoven is a giant of classical music. And the most influential, too—at least, when it comes to piano compositions. That's according to a study in the journal EP J Data Science.

If you're wondering how data analysis could determine something as abstract as cultural influence, it's worth remembering this: Music is the most mathematical of the art form, a lot of which is symbolic. The music is written in symbols that are connected in time.

Juyong Park is a theoretical physicist in South Korea. Park and his colleagues collected 900 piano compositions by 19 composers from 1700 to 1910. Then they used that mathematical quality to their advantage by dividing each composition into what they called "code words", in other words, a chord. They then compared each chord to the chord or note that came after it, which allowed them to determine how creative composers were at coming up with novel transitions.

The composer with top marks for novelty was Rachmaninoff. But when the researchers looked at those chord transitions across all 19 composers, it was Beethoven who was most heavily borrowed from—meaning at least among the composers in this analysis, his influence was the largest.

Their study comes with some drawbacks. For example, the researchers only considered piano compositions in this work, and by only studying chord transitions, so their conclusions wouldn't relate to artists who were influential in other ways like Bach or Mozart. Park explained, "It's well understood that Mozart's contribution to music comes from the musical forms that he designed. That was not very well reflected by our mathematical modeling."

As for Park, the results convinced him he has some listening to do. "Of course I listen to music. I like Rachmaninoff's music, but I have to say I have listened to Beethoven way more than Rachmaninoff. So after this work came out, I ended up buying his whole complete collection.