John and Jack met at the old bench every afternoon. Then they played football. But they didn't have enough money to buy a real football. So Jack made a ball out of old socks covered with a piece of plastic. Every time, the two friends didn't stop kicking and running until very late.

    On Monday afternoon, John and Jack met again at the old bench. Soon the home-made ball was running across the grass. The boys laughed and shouted happily. The ball was stopped by a boy wearing a nice pair of sports shoes. John was upset when he saw it was Steven.

    The next morning, John's mother gave him a bill. “Your uncle sent you a birthday present.”She smiled. John's eyes grew big when he saw the ＄100 bill. Later that day, his mother bought a pair of new sports shoes and a real football.

    That afternoon Steven invited John to play football. Steven did not want Jack to join them only because Jack's sports shoes were dirty. When the game was over, John and Steven walked past the old bench where Jack was sitting. Steven picked up a stone and threw it at him. John, holding his new football in his hands, walked on and did not look back.

    Several days later, as John walked past the old bench, he saw something lying under it. He looked closer and saw it was the home-made ball. John was full of sadness when he saw the ball. As his sadness turned to anger, he picked up his new football and kicked it into the air. Then he walked to the beach, sat down and waited.

    You may get the idea once or twice a year. You come home on a hot summer day, hoping to have a cool bath, and find out there is no water. Then you see how important water is in your everyday life. However, in many parts of the world, water is not just about one's everyday needs.

    In countries like Tanzania, water is hard to get, and the job of collecting water falls on women's shoulders. Girls are often kept home from school to collect water while their brothers stay at school studying. More time spent collecting water means less time for learning. For these girls, "Knowledge is power" is not just words; it is a sad fact in real life. With less time spent at school, their chances of getting well-paid jobs are small. And they often have no voice in important matters, like who to marry. These girls are often married into poor families. They have little money or knowledge to take care of their children, so the children often die young. For the baby girls who are lucky enough to live, their life may still center around "water," just like it did for their mothers.

    Napoga is a girl in Ghana, Africa. It is hard for her family to get clean water. Every morning, she leaves home at half past five to get clean water for her family in a village far away. It takes her six hours to get enough clean water for daily cooking and drinking. She has no time to go to school or to play with her friends. Millions of people in the world are like Napoga. They can't get enough clean water to keep healthy.

    Earth Day is on April 22. But on all the other days, we must also remember it. The water we use is the most important natural resource on the Earth. Water covers about 75% of the Earth's surface. But most of that is sea water. We can't use it for many things. Fresh water covers only less than 1% of the Earth's surface.

    You probably feel lucky that your life isn't as hard as Napoga's. But that doesn't mean you don't have to worry about water. We all face serious water problems. One of them is water pollution Lots of kinds of things from cars, factories, farms and homes make our rivers, lakes and seas dirty. Polluted water is very bad for people to drink. And dirty water is bad for fish too. Now, 34% of all kinds of fishes are dying out. Scientists say that in 30 years, more than half of the people in the world won't have enough clean water. We have to learn how to save more water for ourselves and our children.

    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.

    Some of the greatest problems we face today are the destruction (破坏) of our environment. Brown clouds, polluted water, endangered wild animals…. these problems seem so huge.

    So my family does what we can. We take cloth bags to stores instead of using plastic bags. We walk where we don't have to drive…

    But does it do any good? When I am the only one in line at the market with cloth bags, am I doing any good? Does my walking to stores make any real difference to the world?

    I recently learned something about flamingos(火烈鸟) which like to get together in groups of a thousand or more. Every year, when the time comes for migration(迁徙), a few of them first take off from the lake. But none of the others seem to notice. So the small group returns. However, the next day they try again. This time a few more fly along with them, but most of them still pay no attention, so they return again. They try for several times. Every time a few more birds join in but, since thousands of the others still take no notice, the great migration plan is once more stopped.

    Then one day something changes. The same small group of birds once again starts flying and a small number more join in just as before, then more. Finally, they all take flight and the migration really begins. What a spectacular sight it must be — thousands of flamingos taking off into the sky at once!

    A few can make a difference. Even if you're the one to take the first step, and continue trying, others will someday take notice and together we will solve even our greatest problems.