Better think twice before choosing a password for e-mail, online bank or shopping. Simple passwords are easy to be stolen.

A password is like a key to your home. If someone steals it, he'll get chances to steal something else. We use passwords everywhere in our life. We are so used to passwords that we don't pay any attention to them until we lose or forget one.
A study of 28,000 passwords recently stolen from a popular website showed that people often do the easy thing. It found that 16 percent took a first name as a password. Another 14 percent used the easiest keyboard combinations such as “12345678” or QWERTY. Five percent of the stolen passwords were names of television shows or stars popular with young people. Three percent of the passwords expressed feelings like “I don't care,” “Whatever,” “I love you,” or their opposite, “I hate you.”
Robert Graham, who did the study, advises people to choose a password that is longer than eight characters with one capital letter(大写字母) and one symbol.
Of course, safe passwords don't mean those hard to remember. Forgetting your password is sometimes a big headache for you. Maybe, the perfect password is easy for you and hard for others.

    Only humans speak using words. But all kinds in the animal world can communicate in one way or another. Maybe you have heard about the way bees dance around to send messages to each other and the way dogs bark in different ways to give warnings, to be friendly or to be playful. But did you know about infrasonic communication used by elephants? This is how it works:

    Humans hear low sounds like thunder rumbling in the sky. But we don't hear sounds lower than this. However, animals such as elephants and hippos can hear much lower sounds than humans can. And what's more, they can make those low sounds as well, and they use them to communicate with each other. This is known as infrasound.

    The amazing thing about infrasound is that it travels over several kilometers. Higher-level sounds like the one people can hear, don't travel well through walls, leaves, trees and so on, which is why we can't hear sounds from more than 100 meters away. But infrasound is much stronger and things like grass and trees have no influence on it. Therefore, it can travel much further. Elephants can hear infrasonic calls from four kilometers away!

    There have been reports of people watching groups of elephants feeding or resting and then the elephants suddenly all stopped what they were doing for no reason at all. They obviously heard a warning call from a long way away, but the people didn't hear a sound. In places like a zoo or wildlife park where you can get nearer to animals, it is a bit easier to sense when infrasonic sounds are made. When you stand near mother elephants with their babies in a zoo, you may notice a slight rumbling in the air every few minutes—not loud or strong, but clearly noticed. This is infrasonic communication—the mother elephants “talking” to their babies.

    Mica and her little sister got a tree house this year. "I'm Mica! I love my tree house!" This $28,000 tree house is a gift from their parents. Almost three metres above the ground, the platform (平台) was built between two large trees. "One of the things I really wanted was a little door within the big door. If you go up, you'll find that there is a door handle, which is of the kids' height. And there is an adult size door as well. I told the designer to make it feel like a secret hideout (躲藏处)," said Mica's mother Keenan.

    Bala Sundar and his wife came to America 20 years ago. Unlike Keenan and her husband, who bought a tree house for their daughters, the Sundars got one for themselves. "We wanted to have a regular place where we can relax. So we bought it," he said. With beds, tables and windows, it's a welcoming, comfortable space to spend a summer night.

    Both of these amazing tree houses were created by Dan Wright. He's the founder of Tree Top Builders Inc., and has built more than 400 tree houses since he started the company in 2003. "I think the sense of freedom and independence is why Americans can resonate (共鸣) with tree houses. They get people up off the ground and, for kids, their parents can't reach them anymore. They are up looking down, getting a new perspective on life," said Wright.

    A series of Chinese landscapes (风景) created by an AI (人工智能) robot, named Gemini, is shown in London.

    It was believed to be the first AI-made ink work. Ink Now Chairman Calvin Hui sees it as the start of the tech ink times.

    It took Victor Wong, the Hong Kong artist, around three years to build and program Gemini. He has been interested in traditional art since he was young. "Few younger people nowadays care about ink, so I decided to bring technology and ink art together." says the artist, "I want to tell them that ink painting is not that hard to do."

    Each landscape painting can take around 60 hours to finish. First, the robot artist creates his own landscape in his AI mind. Then he's traveling inside his mind and picking up an angle (角度) because it's 3D. After that he uses an arm that puts the brush into ink and water before sweeping across Xuan paper to create Chinese Shuimo artwork.

    However, in some people's opinion, whether robots can create ink art like human artists is not sure because the ink lines were too, straight while works created by human hands are better. "I'm open to all comments," he said, "I'm keeping an open mind as to whether machine-made art can be seen as art. But I hope it will bring an imagination to artists on how to mix technology while painting or creating.

    How green are you? Do you know how to be green?

    We all need a healthy environment, but we produce waste every day and it does harm to our environment. Though we are young，we can still do something to help. In fact, even the simplest everyday activities can make a real difference to the environment. Here are some ideas for you.

    Reduce

    Reduce means "use less". Don't waste things. This saves money and reduces pollution and waste going into the environment. Before we buy something new, think whether it is really necessary-or maybe the old one will be just as good! When we buy things, choose local products if possible, and try not to buy too many things from abroad.

    Reuse

    Reuse means "use again". Use things for as long as possible. When we buy things, make sure that they last a long time. We should look after them so that they will last, and we should repair them if we can instead of throwing them away and buying new ones. Don't use a paper cup or a paper bag. It's better to use a china(瓷器) cup and a lunch box because you can use them again.

    Recycle

    Recycle means "change things into something else". Though it takes energy to change something into something else, it's better than throwing things away or burning them. Find out what can be recycled in your neighborhood and take part in recycling programs. We should also buy products made from recycled materials, such as recycled paper, to help save trees.

    So please remember these three words: reduce, reuse and recycle.