Coloring is an activity that children worldwide have long enjoyed. With a picture already made for them, kids simply chose a crayon, pencil or marker of their favorite color and fill it in. Today, it also becomes more and more popular among teenagers and even adults, who are enjoying relaxing hours of coloring. In December, five of the top ten best-selling books in the United States were coloring books.

    They are fun, but are coloring books good for you?

    The good feedback(反馈)from customers is encouraging. Trina Lucida, a popular artist creating coloring books, says that many of her customers are buying the coloring books for others who are sick or going through a hard time. She adds that the "big idea" behind her latest book is to encourage people to do something creative.

    Lucida is right, according to Allan Rohan, a psychology(心理学)professor. "Many customers think of coloring books as a new creative stage," he said in an interview, "but what's more important is that people spend time coloring in order to reduce stress after a long day." Research shows that coloring can reduce stress by guiding people to focus on(专注)one simple task. When a person is filling in a flower with a light purple color, he focuses on the flower and forgets about all his troubles in life.

    Experts add that coloring may relieve a certain kind of pain. Doing the coloring helps people relax their mind and calm down. Also, coloring helps people's brain in a healthy way. The shape of the drawing makes one side of the brain active, while the color of the drawing improves the other. Coloring can bring out your imagination and take you back to your childhood. Interesting, isn't it?

    "It's very relaxing," said Susan Jackson, a big fan of Lucida's coloring books. "Coloring frees my mind. And it's not just to try to fill blank(空白的)pages. The pictures make me happy and there is just something about them. So I'm saving the pictures I like best to the very end."

    What will life in the future be like? Will it be much better than it is now? And what will we be able to do in 10, 20 or 30 years' time?

    Genetic engineering (基因工程)may help us make the perfect human. Babies may grow up to play basketball like Yao Ming or look like Cecilia Cheung. Also, we may be able to bring the dead back to life. Maybe people will be able to meet and talk with their dead family members.

    Over the next 20 to 50 years, it will become harder to tell the difference between humans and machines. Perhaps we will be able to make copies of ourselves, so we will appear to be alive long after we are dead. People may be able to find ways of putting the life of a person into a new body.

    Nanobots(纳米机器人)will be important. We will use them when we are sick. For example, when we have a stomachache, we will swallow (吞下) a nanobot and it will travel through our stomach, taking a video of what's happening there. The video will help the doctor cure us.

    In the future, computers may have their feelings. They may be able to think better than us. We may be more and more interested in computers and the internet, spending all our time in front of computers. Perhaps we will forget our real needs. Perhaps we will become super couch potatoes weighing 250 kg!

    Squirrels (松鼠) are getting ready for winter. They are looking for nuts and seeds, digging holes in the ground or finding holes in trees. That's where they store the food they will need during the coming months, when the weather is cold and sometimes snowy.

    Squirrels spend a lot of time in trees, which are like restaurants for them. Among their favorite things to eat are nuts and other parts of trees, like tender buds (花苞).

    Squirrels may also eat corn, insects and other animals. And, as anyone who has a bird knows, squirrels love bird food!

    Squirrels stay active all winter, so they need plenty of food to help keep up their energy. Squirrels tend to bury food underground, piece by piece. Some squirrels may gather food into piles that they put at the base of trees or bury underground.

    When they need food, squirrels use their memory and smell to help them find what they buried. Sometimes, you'll even see them digging through the snow.

    Squirrels make nests in trees. Some squirrels spend much of the winter in underground tunnels (地道), where it is warmer.

    When spring comes, squirrels change their eating habits to new plant growth, like buds and leaves. Sometimes they forget to dig up all their buried nuts.

    That's why you'll sometimes find a little tree growing in a place where neither you nor your family planted it. It must have been the squirrels.

    A new camera made by a company named Netatmo has facial recognition software (人脸识别系统) that can tell parents at work that their children have returned from school, or that a package (包裹) has been taken to their home. It can also tell them if a stranger has entered their home.

    Janina Mattausch is a product marketing manager for Netatmo.

    "The common security (安全) cameras at present are not that smart. So, they can tell you if something is moving but they don't necessarily know if it's a human being or, ah, if it's your kid- they don't know the difference, so they will warn (警告) you all the time."

    When family members enter a home, the new camera "recognizes" (识别) them and sends information to the owner's smartphone. The owner can choose to see the video then or later. But if an unknown person enters a home, the camera will send the owner a warning that will cause an alarm to sound on the owner's smartphone.

    That is what happened recently to a smart home camera owner named Damien. He lives in Paris.

    "On a Friday I was at work, attending a big monthly meeting when my phone warned. At first I told myself 'Oh, it must be a mistake, maybe I have to set the system again.' —but the notice on my phone was telling me that there was a movement in my flat and also a face that the software did not recognize."

    He watched the video and was very surprised by what he saw.

    "I saw a person I did not know with his shoes on. I was watching it live on video. So I felt totally unbelievable, frozen. I asked a workmate to take me back home as fast as possible and I called the police on the way."

    With the help of the video, the police found the intruder (闯入者) later that day.

    This is a street crossing. There are red and green lights at each corner. Drivers must watch the lights carefully.

    When there is a green light, the cars may go on. When there is a red light, the cars must stop.

    They must wait until the red light changes (变成)to green. Then they can go on. Sometimes the cars want to make a right turn or a left turn. They can make a right turn when the light is green or red. But they must wait until the green light is shining (闪亮) if they want to turn left. Some people are color-blind (色盲的). They can't see the difference (不同点) between red and green. These people mustn't drive, or there may be an accident (事故) .We must keep our street safe (安全的).