Can dolphins talk? Maybe they can't talk with words, but they talk with sounds. They show their feelings with sounds.

    Dolphins travel in a group. We call a group of fish“a school(一群)。” They don't study, but they travel together. Dolphins are mammals(哺乳动物)，not fish, but they swim together like fish in a school.

    Dolphins talk to the other dolphins in the school. They give information. They tell when they are happy or sad or afraid. They say” welcome” when a dolphin comes back to the school. They talk when they play.

    They make a few sounds above water. They make many more sounds under water. People cannot hear these sounds because they are very, very high. Scientists make tapes of the sounds and study them.

    Sometimes people catch a dolphin for a large aquarium(水族馆). People can watch the dolphins in a show. Dolphins don't like to be away from their school in an aquarium. They are sad and lonely.

    There are many stories about dolphins. They help people. Sometimes they save somebody's life. Dolphins' meat is good, but people don't like to kill them. They say that dolphins bring good luck. Many people believe this.

    The years from A.D 500 to 1450 are called the Middle ages. Sometimes they are also called the Dark Ages since few people had an education during that time. Still, there were lots of new ideas and inventions. Many of them came from China.

    There are some easy things you can do to protect the environment and the earth. Choose ideas from the list or come up with a few of your own.

    •Plant flowers, grass or trees.

    •Whenever you visit a park or beach, take away what you bring there—keep rubbish in a bag until you can put it in a dustbin.

    •Turn off the lights and TV sets when you leave the room. This can save a lot of electricity.

    •Turn off the tap when you brush your teeth. You can save some water by not letting it run. Also, use a glass cup instead of a paper cup because this saves paper.

    •Keep the doors and windows closed in winter to keep warm air in.

    •Give your old books and magazines to a library instead of throwing them away.

    •Give your old clothes to poor children you know instead of throwing them away.

    •Use both sides of paper.

    •Stop pouring dirty water into the rivers or lakes nearby.

    •Encourage all your friends to do the same things you do to help protect the earth. You don't have to wait until Earth Day to do these things. Make every day Earth Day. If everyone makes a contribution to protecting the environment, the world will become much more beautiful.