April 22 is Earth Day. Everyone on Earth should care about and protect the earth!

The earth has warmed by about 1°F (华氏度) over the past 100 years, but why and how? Well, scientists are not quite sure. Maybe the earth gets warmer and warmer on its own. But many scientists say that people are doing many things which make the earth warmer. First, greenhouse effect (温室效应) is a very important reason for the change of the earth. People give out too much energy into the air every year. It makes the earth warmer. Climate (气候) change is another important reason. Sometimes it becomes too hot and sometimes too cold. Sometimes there is too much rain and sometimes too little. The change of the climate makes the earth warmer. In turn, the warmth of the earth changes the climate, too.

When the earth becomes warmer, there may be more rain and a rise in sea level. It will affect the growth of plants, animals and people. On a Pacific island, 100 people have to move to higher ground because the sea is rising. These people can no longer live on the coast. Before that, two islands without people went underwater in 1999. Scientists say that the seas can rise by nearly one meter by 2100.

People can affect the earth's air, land and water. As for us, we can do many things to protect the earth. For example, we can use fridges less. We can tell more people about protecting the earth.

    We see many animals, like rabbits, bees, dogs, birds, sheep…，but do you know 1these animals say things? First，let's see a rabbit. When a rabbit sees 2dangerous(危险的)，it runs away at once. When it runs, its tail moves up and 3.When others see this, they run away,4.

    Many other animals use this kind of language(语言). When a bee has found some food, it goes back to 5home. It cannot tell6bees where the food is by speaking to them，but it does a little dance in the air. This may tell other bees 7the food is.

    Some animals say things by8sounds like a man does. For example，a dog barks when a stranger(陌生人)comes near. Some birds can make several 9sounds, each with its own meaning. In a word, every animal10its own language.

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    After a long day's study at school, you are very tired. So after school you go home to relax. When you get home, a robot greets you. He's happy to see you and helps you take your school things to your room. He listens to you talk about your school life and tells you a new joke. And he tells you to call your cousin and to say "Happy birthday". And then he helps you with your homework.

    This is your future, and the robot's name is NAO. NAO has a small body, big eyes and a large head. He can walk and dance. He listens and talks, and he even learns and thinks for himself. His creators (创造者) predict that the robot will be in people's homes before 2040.

    This $16,000 robot knows who you are. NAO can even expressemotions (表达情感). He is a self-guided robot. A self-guided robot can sense (感觉), think and act. Other robots might do two out of the three. For example, a robot might sense things using cameras and think using computers, but with no arms, he can't act. Another robot can move and sense things, but he can't think for himself. These aren't self-guided robots. But NAO can do them all.

    Animals are our friends. There are many zoos in the 1It's good to 2 animals in zoos. Zoos have many advantages, I think.

    Firstly, zoos are places for people to see 3 kinds of animals. Without zoos, most people would4see a real bear or tiger.

    5 , zoos can take good care of animals. Zoos give 6 to animals and. clean them on time every day. In the wild, it is not always easy for an animal to find food. So sometimes it goes 7. But animals in zoos never go hungry.

    Thirdly, people protect the animals in zoos and offer them safe places to live 8 Animals are living in zoos safely and happily. In the wild, some kinds of animals are 9 and endangered. But zoos give these animals a chance to live. Without zoos, there would be 10 kinds of animals in the world.  People should do more things to protect animals.

    Life in the year 3044 is very different 1  life in the 21st century. We still do many of the things you do, but we do them 2  For example, we now have e-friends to help us and company us. An e-friend is a machine that looks just 3 a human being. It can walk and talk and can do almost 4 we human beings do. My e- friend is a lot like me and we have 5 fun together. She helps me 6 my homework and we often go swimming. She is programmed to take care of me if anything 7, so I always feel safe when we are together.  She can also send me messages, just like old-fashioned emails, and I can download information from her memory. It's great  8an e-friend--I am never lonely and I always have someone to talk 9.

    I would like to tell you more about life in the year 3044, but I have to send my e-friend to clean up my room. Maybe 10 I will be able to travel back in time and visit you.