Although cats may be one of the most popular pets today, little is known about how and when humans and cats set up their close relationship.

    The earliest evidence for human–cat interaction dates back to prehistoric Cyprus(史前塞浦路斯), where the remains of a wild cat and a human — dated 9,500 years old — were found buried together

A new study in the Proceedings of the National Academy of Sciences has confirmed the first direct evidence of a human–domestic cat relationship among Chinese farmers 5,300 years ago. Researchers studied the bones of cats, dogs, deer and other animals unearthed in an excavation (挖掘) near a village in Central China. By using some ways, scientists showed that the cats were living on a mostly millet(黍)–based diet, just like the domesticated dogs and pigs from the site.

"The most reasonable explanation for a high consumption of millet–based food is that the cats had formed a stable and mutual relationship with humans and could easily feed on rodents (啮齿动物) around human villages, find leftover food or even have been fed by people intentionally," said Hu Yaowu from the Chinese Academy of Sciences in Beijing, whose research focuses on the relationship between humans and domesticated animals.

    "It is very interesting for us to find the consumption of millet-based foods by the cats, since this kind of evidence had long been missing.” Hu explains. Since cats usually eat meat, such a diet would be unexpected, unless the cats were being fed by people, the study argues. The researchers also found that one of the cats survived to reach old age, implying that it had a safe place to live and enough to eat.

Why the farmers wanted to keep cats nearby or make them "pets" could be answered by other evidence. Chinese archaeologists found some storage containers were specifically designed to keep out rodents — a vermin (害兽) that cats could certainly have helped with.

The simplified theory is that rats were attracted to the food of farmers, and so were harmful to farmers. Cats were attracted to the rats, and so farmers formed a mutually beneficial relationship with cats, taking care of them in return for pest control.

    Is your TV connected to the Internet? What about your chair, or your fridge? Probably they are not. But in the future, most things in your home may be connected, as the so-called "Internet of things" is developing.

    The Internet of things may be coming sooner than you think. In 2015, Samsung CEO spent a lot of time talking about the Internet of things. He said that in the next five years, every Samsung product will be part of the Internet of things, whether it's a vacuum cleaner or a washing machine.

    So, how do household objects that are part of the Internet of things work? Well, think of a common chair. When connected to the Internet, the chair warms up when it knows that the user has just walked into the room and is feeling cold.

    An Internet-connected camera could help people feel safer in their homes. It can recognize people's faces, and even can see when someone passes by and send you a message on your smartphone to let you know who's there. If the person is someone you don't know, it can tell you that, too.

    But according to MIT Technology Review, whether companies are connecting dog food bowls or security systems to the Internet, there may be some problems. For example, many early connected-home devices (装置) don't have much built-in security, which means they could be hacked (被黑客攻击). In addition, it could be difficult to get these devices to work together especially when they are made by different companies. To fight this, many companies have joined the Open Connectivity Foundation, which has more than 300 members now.

    So, picture this: you enter your home. The temperature changes to make you feel comfortable. Your favourite music starts playing for you. Do you think that this would be a good thing? It may happen sooner than you think.

    Trees are one of the oldest " citizens (公民) " of our Earth. They keep our air clean, reduce noise pollution, improve water quality and provide food and building materials.

    Just like us, trees change a lot as they grow. At 1 to 3 years old, young trees learn how to protect themselves. For example, many trees grow thorns( 刺) to warn animals not to go near. Most young trees have large, deep green leaves so that they can catch enough sunlight and change it into their food and energy.

    When trees are 4 years old, they begin to grow very rapidly and become strong enough to face challenges later in life. At the age of 15, trees become young adults. They grow more slowly and begin to produce flowers and fruit.

    It is not until the tree is 20 to 25 years old that it becomes a real adult. The tree reaches its largest size. The adult tree gives us shade, oxygen and natural beauty; it is also a great place for a tree house, or a place for us to read a book, listen to music and so on. If we give the adult tree proper care, it will go on to live healthily for many years.

    Gradually, trees begin to grow older and older and even die. At this time, they still have their important place in nature. When a tree becomes hollow (空心的) or part of it becomes dead, it provides a home to small animals and is a source of food for many other animals.

    In many ways, the life of a tree is similar to our own life experience. When we are looking at the life of a tree, we learn about that each period of life brings its own form of joy and challenge.

    Enjoy every minute of the life of the trees and take care of the trees!

    People in Western countries are eating less meat these days, whether for their health or because they want to protect animals. But now they have another reason.

    Eating less meat can help to prevent climate change, according to a recent study published in Nature.

    Raising livestock (家畜) is bad for the environment. When animals like cows digest (消化) food, their stomachs make greenhouse gases, which are a major cause of global warming. Seventeen percent of greenhouse gas emissions (排放) come from livestock farming, The New York Times reported.

    In addition, to raise these livestock, people have to cut down forests and turn them into farms. Forests play a key role in fighting global warming because they absorb greenhouse gases.

    Eating less meat according to certain guidelines could cut global food-related emissions by nearly a third by 2050, the study found. Maintaining (保持) a vegetarian diet in the long term could bring down emissions by 63 percent.

    But eating less meat won't be easy. According to the study, people in Western countries will need to eat 90 percent less meat than they do now in order to have an impact (影响) on our climate. Scientists are now trying to find new foods to replace meat.

    Some say that insects (昆虫) could help. A 2013 UN report said that eating insects is healthier and better for the environment. They produce 75 percent less greenhouse gases than livestock.

    Some experts are creating lab-grown meat. They make meat in a lab using livestock cells (细胞). In March, US company JUST said people in the US might be able to buy its lab-grown meat by the end of this year.

Almost everyone has a question or two about living in space. What is life really like in space? And what do astronauts do there?

Astronauts living in space have the same hygiene(卫生) needs as people do on the earth. When they wake up, they wash their hair, brush their teeth and go to the bathroom as well. However, because of microgravity(微重力), astronauts have to use a kind of special matter to wash their hair and use leg restraints(安全装置) to place themselves when they use the toilet.

Astronauts eat three meals a day: breakfast, lunch and dinner. Some food can be eaten in the natural form such as fruit. Other food needs water such as noodles. There are no fridges in space, so space food must be stored and prepared correctly and they won't go bad.

Besides morning routine (常规) and eating in space, astronauts perform many tasks, such as checking the machines and updating(更新)computer equipment. At the same time, the control centre on the earth sends messages to the astronauts through voice or email with new instructions to help them with their daily work.

What's more, living in space is not just all work and no play. They can enjoy themselves by looking out of the window, watching movies, reading books, playing cards and talking to their families during their free time.

Tom and Tony are brothers. Tom exercises every day. He plays soccer five times a week and he swims and runs every weekend. He drinks milk and eats fruit and vegetables every day. He doesn't eat junk food. He sleeps eight hours every night.

Tony doesn't like to exercise, but he sometimes plays soccer with his brother. He really likes to watch TV. He watches TV for four or five hours every night. He never drinks milk, and he hardly ever eats fruit and vegetables. He loves junk food. He eats junk food five or six times a week. He often plays computer games, too. He sleeps eight hours every night.