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.

    In the most southern part of our planet, there's a place that's covered with snow and ice all year round. But it has the clearest and cleanest air. Amazingly, in this place, the sun sometimes hangs even in the midnight sky. This place is Antarctica (南极洲): the coldest, windiest and harshest (恶劣的) place on the Earth.

    As the world's least-known place, Antarctica is of great interest to scientists around the world. During 30 years, China has sent many scientists to Antarctica. They mostly look at the resources under the icy land and do research about climate change and marine (海洋的) biology.

    Antarctica is a place with fantastic views. However, life there is very hard. Food is one of the biggest problems. Frozen food which can be heated easily is people's daily food. Fresh vegetables are hard to grow in the cold weather.

    Sleep is also difficult. In Antarctica, summer lasts from November to March. During this period, Antarctica points to the sun and receives sunlight 24 hours a day. In order to get some sleep, scientists cover the windows with black plastic cloth to create "night".

    Working in Antarctica is dangerous, especially when meeting gale-force (七级以上的) winds. They can easily blow people away. So there are ropes that connect buildings of some research stations. People can hold these ropes to keep their balance in forceful winds.

    What's morel communicating with others is difficult. Without cables and Internet in some research stations, two-way radios are the only tools to communicate. If people want to say hello to friends and relatives, they can use satellite phones.

    Although it is challenging to work in Antarctica, scientists' passion to learn about this mysterious land will never end. It is hopeful that one day they will step every corner of this icy land.

    1970 was World Conservation(保护) Year. The United Nations wanted everyone to know that the world was in danger. They hoped something could be" done.

    Here is one example of the problem. At one time there were 1,300 kinds of plants, trees and flowers in Holland(荷兰), but now only 866 are left. The others have been destroyed (毁灭) by modern people and their science. We are polluting earth, air, water and everything around us. We can't live without these things. If things go on like this, we shall destroy ourselves.

    What will happen in the future? Perhaps it's more important to ask "What must we do?". More and more young people have known this. Many of them are helping to save our earth. For example, they plant trees. In a small town in the United States a large group of girls cleaned the banks of 11 kilometres of their river. Young people may hear about conservation through a song called "No one's going to change our world". It was made by Cliff Gichard and other singers. The money from it will help to conserve tigers, elephants and pandas on the earth.

    George: What are you doing?

    User: Saying hello to you.

    George: Are you a monkey?

    User: Do you think monkeys can type?

    George: Sure.

    User: Are you a monkey?

    George: Do you think monkeys can type?

    User: You told me they could.

    This is a conversation between a human "user" and a computer. The computer was made to be as human as possible. It was taught to talk to humans. It has also learnt from what people have said to it. This has helped it become more human.

    What makes George talk is called Jabberwacky. It won the Loebner Prize not long ago. The prize is a contest to find the most realistic artificial intelligence (现实的人工智能). In 2006, scientists talked to the computer. They typed questions to it, and it answered.

    Jabberwacky first appeared in 1982. It has been gelling better every year since then. The list of things that the computer says to a human is getting bigger and bigger. It means the computer has more things to say when you talk to it.

    It is hoped that a computer like this will do our jobs in call centres. When Jabberwacky is more realistic, this will be possible.

    Animals, including insects, do not have a language like ours. They do not talk to each other in words and sentences. But if we watch them, we can see that they do have ways of communicating with each other.

    Can you see the rabbit's tail which is moving up and down? When rabbits see this white tail moving up and down, they run too. They know that there is danger. The rabbit has told them something without making a sound. It has done this by using its body language.

    Many other animals use this kind of language. When a cobra is angry, it raises its hood and makes itself look fierce. This warns other animals. When a bee has found some food, it goes back to its home. It cannot tell the other bees where the food is by speaking to them, but it does a little dance in the air. This tells the bees where the food is.

    Some animals say things by making sounds. A dog barks, for example, when a stranger comes near. A cat purrs when pleased. Some birds make several different sounds, each with its own meaning. Sometimes we human beings speak in the same way. We make sounds like "Oh" or "Ah!" when we are frightened or pleased or when we drop something on our toes.

    But we have something that no animals have—a large number of words that have the meanings of things, actions, feelings or ideas. We are able to give each other all kinds of different information in words and sentences, which no other animals can do. No other animals have so wonderful a language as we have.