Radio, telephone and TV are widely used in the world. When you turn on the radio, you can listen. But when you use telephone, not only can you listen to others but also you can chat with them, however, you can't see anything at all. TV is much better than both of them. People can watch TV and listen to it, but they can't take part in what they see.

    Today, some people are using a type of telephone called vision-phone（可视电话）. With it, two people who are talking can see each other. It is better than radio, telephone or TV.

    Vision-phones can be of great use when you have something to show the person whom you are calling. It will be helpful in people's life. Some day you may be able to call up a library and ask to read a book on your vision-phone. You may be able to do some shopping too. Perhaps in the future, people will use vision-phone.

    Ladies and gentlemen, I returned to this year in a time machine. In the year 2500, we are able to travel through time to any year in the history of the earth. This year is your last chance your lifestyle to save the earth.

    Beginning in the middle of the 20th century, a few people were worried about polluting the earth's water and air, but most people did not change their way of life. Instead, they continued to pour(倒) dangerous chemical(化学物品) and other waste into lakes and seas, to drive more and more cars and trucks, and to cut down trees.

By the year 2200, the earth's water was completely polluted. People could no longer drink water, and they had to use other types of liquids(液体). Scientists said that in the future there might be too many people on the earth. But not enough was done.

So by the year 2300, there were so many people that food became scarce. There was no water to grow food and all of the fish in lakes and seas died because of pollution. Terrible wars broke out between the rich and the poor. Scientists were working very hard to find another planet in space where humans could live.

By the year 2400, the air was too polluted for humans to breathe. So we had to leave the earth. But only the rich were able to leave. Where did we go? Nowhere. And everywhere. You see scientists did not find another safe planet, so now we must travel around the universe in our space ships. We are still looking for a place to call our home.

    So it is up to you to change history. There is still hope. You must change your lifestyle now, before it is too late.

    Friendship between animals sometimes seems stronger than that between men.

    In France, a man had to move to a new job two hundred kilometers away. He had a dog and a cat, and he loved them both. But he thought that the cat would like to stay in the same house with new owners. So he moved and took only the dog.

    About three weeks later, the dog was suddenly lost. For several days, the man looked for his dog, but didn't find him. Then, seven weeks later, the dog came back but he was not alone. By his side was the cat. They were tired and hungry after their long trip. And they never left each other again.

    Another story is about goldfish. We usually think fish are cold-hearted, but sometimes we may be wrong. A friend had to work in another country. So I took her pet goldfish and put it in a bowl with mine. They two lived together for six months. When the friend came back, she took her fish home.

    Then, I found my goldfish was acting strangely, hitting against the side of the bowl. The next morning he died. Later that day, my friend phoned to say that her goldfish was also dead. I believe they died of sadness.

    We all cry for water when we are thirsty. But do you know, in very hot, dry weather, plants also make very low sounds as if they are crying for help?

    You see, in a plant's stem there are several hundred "water pipes" that bring water from soil all the way up to the leaves. When the ground turns dry, it becomes harder and harder for plants to do this.

    On very hot days, plants have to get any water that they can get.

    Scientist Robot Winter has found out that when plants can get no water, their "water pipes" snap(发出声音). When that happens, the whole plant vibrates(振动) a little.

    Robot knows that healthy, well-watered plants are quiet.  He also knows that dry plants are many insects' "favourite" and they often attack(袭击) them. How do the insects know which are healthy plants and which are not? Robot thinks that the insects may hear the plants "crying" and they may come to kill them.

    Many people thought a computer wasn't supposed to be able to beat a top master at the ancient Chinese game, Weiqi, for at least another 10 years. But AlphaGo, an artificially intelligent system (人工智能系统) designed by Google, made it. It easily beat Lee Sedol last year, one of the best players in the world. It challenged the world's top players to show how much progress it had made over the past few years.

    In late May, 2017, AlphaGo appeared in China and played against 19-year-old Ke Jie in Wuzhen, China. He is No. 1 player now in the world. However, the result wasn't out of people's expectation. He lost the match. Though Ke Jie tried his best and he once saw the victory just a step away, he lost his best chance when he became excited.

    At the press conference (新闻发布会) after the match, Ke Jie was interviewed by the reporters. He said he had realized how powerful AlphaGo was, and it was getting perfect. When a Chinese reporter asked him in English, the reporter spoke so fast that the interpreter (口译员) couldn't catch him. Ke Jie got kind of angry and told him that it was unnecessary for two Chinese to speak in English. The reporter apologized to him and offered to ask him for a coffee.

    The cat and mouse game is over, but the challenge between man and robots will still go on.