Earth is our home. It has air that we can breathe(呼吸). It has water for us to drink. It has plants and animals that we can eat. Earth is not too hot or too cold for us. It has everything we need to live.

    We are on earth, but we call see things that are not on earth. Early in the morning, we can see the sun comes up. All day, the sun seems to move across the sky. Later in the day, we can see the sun goes down. But the sun is not really moving around us. We are the ones who are moving. Every morning, we turn towards the sun. Every night, we turn away from it. Every year, we go around it. Earth is our spaceship. All of us in the spaceship are riding around the sun.

    At night, we can often see the moon and stars. From earth stars look like little points of light because they are so far away. But stars are really big. A star is a great mass of burning gas. It gives off light and heat. Our sun is a star.

    There are eight planets moving around our sun. Earth is the third planet around the sun. Some of the planets have moons. A moon goes around a planet just as a planet goes around a star. Earth has only one moon. Some planets have more.

    March 20th is World Water Day every year. According to a report from the United Nations, more than half of the world's major rivers have serious water loss and are polluted.

    The Yellow River, the world's fifth longest river, watered some of the oldest farms on earth.

    {#blank#}1{#/blank#}Its source（源头）on Qinghai-Tibet Plateau is drying up. In most of the past 35 years, it didn't reach the sea.

    The Nile in Egypt, running 6, 650 km, is the longest river in the world.{#blank#}2{#/blank#}Now it is down to 2 billion m³ or so. Australia's Murray River reaches the sea only every other year. One fifth of America's Rio Grande has no water, either.

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    Mostly it's damming（筑坝）and global warming that make rivers dry.{#blank#}4{#/blank#}Now about 45, 000 of them lie across the world's rivers. They hold back around 15% of the world's fresh water from running to the sea.

{#blank#}5{#/blank#}Warmer weather takes water away. The glacier（冰川）are becoming smaller. The source of the Yellow River is drying up because of it. Global warming has had certain effects on water sources. Droughts （干旱） happening around the world make people pay more attention to this fact.

    Once upon a time, there was an island where all the feelings and senses, including Love, Happiness, Sadness and Wisdom lived. One day they were told that the island would sink(下沉), so they all got on boats and left except Love.

    Love was the only one that stayed until the last possible moment. Finally, Love decided to ask for help.

    Wealth was passing by Love in a beautiful boat.  Love said, "Wealth, can you take me with you?"

    Wealth answered, "No, I can't. There is a lot of gold and silver in my boat. There is no room for you."

    Love decided to ask Pride, who was also passing by in a beautiful ship. "Pride, please help me!"

    "I can't help you, love. You are all wet and might damage(损坏)my boat," Pride answered.

    Sadness was close by, so Love asked, "Sadness, let me go with you."

    "Oh…Love, I'm so sad. How can I take someone else with me?"

    Happiness passed by Love too.  But she was so happy that she did not even hear when Love called out to her.

    Suddenly, there was a voice, "Come, Love, I'll take you." It was an elder. Love was so excited that he forgot to ask the elder where they were going. When they arrived at the river bank(河岸), the elder went his own way. Love was grateful to the elder, so he asked Wisdom, another elder. "Who helped me?"

    "It was Time," Wisdom answered.

    "Time?" asked Love.

    Wisdom smiled and replied, "Only Time can understand how valuable you are."