When I was six, Dad brought home a dog one day, who was called “Brownie”. My brothers and I all loved Brownie and did different things with her. One of us would walk her, another would feed her, then there were baths, playing catch and many other games. Brownie, in return, loved each and every one of us. One thing that most touched my heart was that she would go to whoever was sick and just be with them. We always felt better when she was around.

    One day, as I was getting her food, she chewed up(咬破)one of Dad's shoes, which had to be thrown away in the end. I knew Dad would be mad and I had to let her know what she did was wrong. When I looked at her and said, “Bad girl,” she looked down at the ground and then went and hid. I saw a tear in her eyes.

    Brownie turned out to be more than just our family pet. She went everywhere with us. People would stop and ask if they could pat her. Of course she'd let anyone pat her. She was just the most lovable dog. There were many times when we'd be out walking and a small child would come over and pull on her hair. she never barked(吠) or tried to get away. Funny thing is that she would smile. This frightened people because they thought she was showing her teeth. Far from the truth, she loved everyone.

    Now many years have passed since Brownie died of old age. I still miss days when she was with us.

    Dreams can be familiar and strange, fantastical or boring, but some dreams might be connected to the mental processes that help us learn. No one knows for certain why people dream, but some dreams might be connected to the mental processes that help us learn. In a recent study, scientists found a connection between nap-time dreams and better memory in people who were learning a new skill.

    In the study, 99 college students between the ages of 18 and 30 each spent an hour on a computer, trying to get through a virtual maze(迷宫). The maze was difficult, and the study participants had to start in a different place each time they tried — making it even more difficult. They were also told to find a particular picture of a tree and remember where it was.

    For the first 90 minutes of a five-hour break, half of the participants stayed awake and half were told to take a short nap. Participants who stayed awake were asked to describe their thoughts. Participants who took a nap were asked about their dream after sleep — and they were awakened within a minute of sleep to describe their dreams.

    Stickgold, a neuroscientist (神经科学家), to know what people were dreaming about when their eyes weren't moving, during sleep.

    Four of the 50 people who slept said their dreams were connected to the maze. Some dreamed about the music that had been playing when they were working; others said they dreamed about seeing people in the maze. When these four people tried the computer maze again, they were able to find the tree faster than before their naps.

    Stickgold suggests the dream itself doesn't help a person learn — it's the other way around. He suspects that the dream was caused by the brain processes associated with learning.

    All four of the people who dreamed about the task had done poorly the first time, which makes Stickgold wonder if the dreams show up when a person finds a new task particularly difficult. People who had other dreams, or people who didn't take a nap, didn't show the same improvement.

    Why do you go to the library? For books, yes－but you like books because they tell stories. You hope to get lost in a story or be transported into someone else's life. At one type of library, you can do just that－even though there's not a single book.

    At a Human Library, instead of books, you can "borrow" people. Individuals volunteer as human "books" and participants in the event can "read" the book－meaning they would have a one-on-one conversation with the volunteer and share in a dialogue about that individual's experience. "Books" are volunteers from all walks of life who have experienced discrimination (歧视) based on race, religion, class, gender identity, age, lifestyle choices, disability and other aspects of their life.

    For a certain amount of time, you can ask them questions and listen to their stories, which are as fascinating and as attractive as any you can find in a book. Many of the stories have to do with some kind of stereotype. You can speak with a refugee (难民), a soldier suffering from PTSD, a homeless person or a woman living with HIV. The Human Library encourages people to challenge their own long-held beliefs to truly get to know, and learn from someone they might otherwise make a quick judgment about.

    According to its website, the Human Library is "a place where difficult questions are expected, appreciated and answered." It provides the opportunity for the community to share and understand the experiences of others in their community.

    The Human Library Organization came to be in Copenhagen, Denmark in 2000. Ronni Abergel and his colleagues hosted a four-day event during a major Northern European festival, hoping to raise awareness about violence among youth. After the success of this event, Abergel founded the Human Library Organization, which has been growing ever since.

    Though there are a few permanent human libraries, most aren't places at all, but events. Though many do take place at physical libraries, you don't need a library card－anyone can come and be part of the experience. There have been human library events all over the globe, in universities and in pubs, from Chicago to Tunis to Edinburgh to San Antonio.

    The stories these "books" tell range from fascinating to heartbreaking and everything in between. And that's the very point of the organization－to prove that no person can be summed up in just one word. It seeks to show people that you truly can't judge a book by its cover－or by its title or label.

    We've all had cases where we've waited just a bit too long to pay an electric bill or speeding ticket. But one man, from California by reasonable assumption, who goes by “Dave”, recently took procrastination (拖延) one step further, by paying a parking ticket almost a half-century after it was given.

    In December 2018, the Minersville Police Department in Pennsylvania received a letter in the mail. Whoever wrote the letter decided it was best to keep his name somewhat unknown, so he put the return address as “Wayward Road, Anytown California” under the name “Feeling guilty”.

    When the officers opened the envelope, they found a brief letter, along with a $5 bill, and a parking ticket dating all the way back to 1974.The note read, “Dear PD, I've been carrying this ticket around for 40 plus years always intending to pay. Forgive me if I don't give you my info. With respect, Dave.”

    Even though the initial parking ticket was only for $2, “Dave” must have felt awfully guilty because he left 150 percent, or $3, in interest.

    Michael Combs, the Police Chief of the Minersville Police Department, stated in an interview that the same ticket would cost about $20 if it was given today. Combs went on to share that the original ticket from 1974 was given to a vehicle that had an Ohio license plate.

    Because there was no system for tracking tickets given to out-of-state cars back then, “Dave” could have gotten away with never paying the $2 fine. But apparently, guilt got the best of him, and he decided to finally cough up the money more than 40 years past its due date.

    When people see machines that respond like humans, or computers that perform amazing feats of strategy, they sometimes joke about a future in which humanity will need to accept robot overlords. But buried in the joke is a seed of unease. Science fiction writing and popular movies have shown us about artificial intelligence (AI) that exceeds the expectations of its creators and escapes their control, eventually outcompeting and enslaving humans or targeting them for extinction(灭绝).

    Even in the real word, not everyone is ready to welcome AI with open arms. In recent years, as computer scientists have pushed the boundaries of what AI can accomplish, leading figures in technology and science have warmed about the frightening dangers that artificial intelligence may pose to humanity, even suggesting that AI capabilities could destroy the human race.

    But why are people so frightened about the idea of AI?

    Elon Musk is one of the famous voices that have raised red flags about AI, In July 2017. Musk told attendees at a meeting of the National Governors Association, I have exposured to the very cutting-edge Al, and I think people should be really concerned about it. I keep sounding the alarm bell. But until people see robots going down the street killing people, they don't know how to react, because it seems so impossible."

    Earlier, in 2014, Musk had labeled AI "our biggest existential threat," and in August 2017, he declared that humanity faced a greater risk from AI than the terrorists. Physicist Stephen Hawking, who died on March14, also expressed concerns about AI, telling the BBC in 2014 that "the development of full artificial intelligence could spell the end of the human race.

    Put an ice cube from your fridge into a glass of water. You have a piece of string (线) 10 centimeters long. The problem is to take out that piece of ice with the help of the string. But you must not touch the ice with your fingers.

    You may ask your friends to try to do that when you are having dinner together. There is a saltcellar on the table. You must use salt when you carry out this experiment.

    First you put the string across the piece of ice. Then put some salt on the ice. Salt makes ice melt (融化). The ice round the string will begin to melt. But when it melts, it will lose heat. The cold ice cube will make the salt water freeze again.

    After a minute or two you may raise the piece of string and with it you will raise your piece of ice!

    This experiment can be very useful to you. If, for example, there is ice near the door of your house, you must use very much salt to melt all the ice. If you don't put enough salt, the water will freeze again.