Part of the fun of watching sports events is following an exciting rivalry (竞争关系).

    But where do all these rivalries come from?

    Some rivalries start because athletes spend a lot of time close to opponents (对手).

    Other rivalries get personal. Things that one rival says that are thought to be not respectful to the other can cause a rivalry, even if the words are misunderstood. And sometimes, rivalries grow just because the athletes don't like each other's personalities.

    Some sports may also be more likely than others to cause rivalries. “Some sports only meet a few times, so there is less chance for rivalries to build,” For example, in sports where athletes perform on their own, such as diving, rivalries might also take longer to appear than in sports in which athletes compete at the same time. But in tennis, players often face each other, and rivalries are more likely to happen.

    So do the rivalries do good or harm to the athletes?

    Some believe that rivalries can be a good thing because they encourage athletes to try harder to win. But rivalries can also become too personal, taking athletes' attention away from their sports.

    Keegan agreed that rivalries often do athletes more harm than good. “They can be a huge distraction (分散注意力的事) and lead to focusing on the opponent more than the game,” he said.

    “Top athletes often have physical and mental training that they follow in order to worry less and prepare to compete”, Gould further explained. An important part of that preparation is preventing from distractions, including rivalries.

    “The better athletes don't care too much about a rivalry – they try to treat every competition the same,” Gould told LiveScience.

    My wife and I owned two doge that we had owned before we met and brought into the marriage. Her dog was a pit bull(斗牛犬) named Zack, and he hated me. When our daughter was born, I was worried that the family pit bull would be dangerous to have around our young daughter. I warned my wife that the dog would have to go at the first sign of trouble. I said, “If he nips(啃咬) at the baby, he's gone.”

    We brought our daughter home in a car seat, and both dogs sniffed(嗅）and licked her, tails wagging. I had to pull Zack away from her because he wouldn't stop licking her. Zack immediately became my daughter's protector, and when she was lying on a blanket on the floor, he always had one foot on the blanket.

    Zack loved my daughter extremely, and when she became a little older always walked her to bed, and then slept on the bed with her. He somehow knew whenever it was time to go upstairs, and he would wait at the bottom of the stairs for her, and then follow her up to bed.

    Zack was poisoned by some neighbor kids, and we had one of the worst days of our lives. Watching my daughter say goodbye to him as he lay still on the kitchen floor, my wife and I were both sobbing.

    At 8:00 that night, my daughter walked to the stairs to go to bed. At that moment, all three of us realized what was about to happen. My daughter looked at her mother and me with a look of horror and panic. It was at that moment that my dog, Sam who loved my daughter dearly, stood up, walked over to her, and nudged her with his head. He put his foot on the stairs, and looked up at her. They walked up to bed, with my daughter holding his neck tightly.

    For the next six years, until he died, Sam waited for her by the stairs each night.

    Everyone needs friends. We all like to feel close to someone. It is nice to have a friend to talk，laugh and do things with. Surely，there are times when we need to be alone. We don't always want people around. But we would feel lonely if we never had a friend.

    No two people are the same. Sometimes friends don't get along well，which doesn't mean that they no longer like each other. Most of the time they will go on being friends. Sometimes friends move away，then we feel very sad. We miss them much，but we can call them and write to them. Maybe we would never see them again，and we can make new friends. It is surprising to find out how much we like new people when we get to know them. Families sometimes name their children after a close friend. Many places are named after men and women，if they are friendly to people in a town. Some libraries are named this way. So are some schools. We think of these people when we go to these places.

    There's more good news for people who have friends. They live longer than those people who don't. Why? It could be that they are happier. Being happy helps you stay well. Or it could be just knowing that someone cares. If someone cares about you，you take better care of yourself.

    Joey was born in 1990 in Connecticut and now lives in North Carolina in the United States. When Joey was six, he started racing small cars in competitions. He began to win many races, but they weren't big races. His parents decided to move to Atlanta, Georgia, so Joey could compete in bigger and better competitions. When he was 12, he set a record by winning 14 races in a row at the Atlanta Motor Speedway. He continued to win many races, and finally began racing with regular-sized (正常大小的) race cars.

    When Joey was 15 years old, he met the race car driver Mark Martin. Martin is a famous NASCAR driver. NASCAR is the National Association for Stock Car Auto Racing, and it is the biggest and most popular car-racing organization in the United States. Martin was interested in Joey and thought he was “the real deal.” He said, “I am sure that he can be one of the greatest that ever raced in NASCAR. There's no doubt in my mind.”

    Martin was right. Joey started as a NASCAR driver in 2007. NASCAR has many races, and at first, Joey was only able to compete in smaller races because of his age. In his first NASCAR season, he won a championship (冠军). In 2008, he was able to compete in bigger NASCAR competitions. He competed in one of the top NASCAR racing series called the Nationwide Series, and at 18, he became the youngest winner in Nationwide Series history.

    In 2009, he became the youngest winner in another top NASCAR racing series called the Sprint Cup Series, and he also won the Nationwide Series for the fifth time. To be one of the best drivers in the history of racing, Joey has to win many more races. But at 19, he's off to a good start.

    It seems we're always being told to get more sleep. Studies suggest spending less time on sleep can lead to obesity(肥胖) and even cancer. You might even find yourself with a head full of false memories. But rarely does science explore the dark side of sleeping too much. That's because few of us in today's busy world have the luck of exploring that option.

    In an August 2018 study, published in the Journal of the American Heart Association, researchers researched the sleep patterns of those "fortunate" few and found they may not be so lucky after all. In fact, they found people who get more than eight hours of sleep have greater health risk compared to those who sleep together less than seven hours. What's more, sleep-aholics-those who manage to get 10 hours a night-stand a 30 percent higher chance of dying compared to the seven-hour crowd.

    The wide-ranging global study involved(涉及) more than three million people who self-reported on their sleep habits and came to an eye-opening conclusion: If you tend to sleep a lot, you may want to buy an alarm clock. As with all things in life, sleep is best taken in moderation(适度).

    You may be thinking: What if I only sleep in on Saturday and Sunday, am I still at risk? The answer is yes, according to a 2019 study published in Current Biology.  Researchers discovered that even if a person sleeps more than seven hours on the weekends but still sleeps less than that on weeknights, they are at risk of gaining weight and developing sensitivity to insulin, which controls the level of sugar in blood.

    For the study, 36 participants were divided into three groups that each had a different sleep schedule: nine hours every night, five hours every night, and five hours from Monday to Friday and sleeping much on weekends. People who get too much sleep tend to feel tired and lack energy. Also, both sleep-deprived(睡眠不足的) groups consume more food and gain weight.

Scientists have discovered a bit of hand-made string (线绳) that's around 50,000 years old in Neanderthal remains. The first Neanderthal remains were found in the Neander Valley in Germany, which is where the name comes from. Neanderthals may have lived mainly in caves and made stone tools, but recent discoveries have given hints that Neanderthals developed some advanced skills that people used to think impossible. For example, Neanderthals knew how to make glue from the bark (树皮) of a tree.

Now, scientists report they've found a piece of string on a stone tool made by Neanderthals. Before this, the oldest known piece of string was one made by humans about 19,000 years ago. The string is about a quarter of an inch long. Almost all things made from plants during that time have broken down and disappeared, so it's very special to find this bit of string.

The scientists don't know whether the string was attached to the tool. But that doesn't interest them as much as the fact that Neanderthals knew how to make string. Bruce Hardy, the lead scientist on the project, says that knowing how to make string was meaningful for humans. "We wouldn't really be here today without that technology," he says.

Making string is a very arduous process. This string was made from the inside bark of an evergreen tree. To make string that is strong enough, the string must be made of several smaller fibers twisted (缠绕) together in a special way. For the Neanderthal string, several fibers needed to be twisted together into something like yarn. Then three pieces of yam needed to be twisted together in the opposite direction to make the final string.

The scientists aren't sure what the string was used for, but they say that string like. the bit that was found could be used to make bags, baskets, traps, or other things. The researchers also suggest that because Neanderthals needed to make pairs and count fibers to make the string, the bit of string may also tell us something about the kinds of math that Neanderthals could do.