Parents today also worry about their children's diets. Some doctors give the following advice：

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      There are too many cities around the world. And each city needs water in many ways. Water on Earth falls mainly as rain. So the rainfall (降雨量) is important to each part of the world. And it is different from one city to another. The following chart shows the average (平均的) rain fall in four different cities in July and January.

    Many wild animals, such as pandas, are in d{#blank#}1{#/blank#}. Often there is not e{#blank#}2{#/blank#} land or forests, so the animals do not have a safe place to live.

    There are only about 1,600 pandas in the wild today. Pandas do not have many babies, and baby pandas often d{#blank#}3{#/blank#}. The situation is getting more and more difficult. We need to p{#blank#}4{#/blank#} them.

    The government is s{#blank#}5{#/blank#} up nature parks and the pandas live in peace there.

    Do you know why different animals or pests (昆虫) have their special colors? Colors in them seem to be used mainly to protect themselves.

    Some birds like eating locusts (蝗虫), but birds cannot easily catch them. Why? It is because locusts change their colors together with the change of the colors of crops(庄稼). When crops are green, locusts look green. But as the harvest time comes, locusts change to the same brown color as crops have. Some other pests with different colors from plants are easily found and eaten by others. So they have to hide themselves for lives and appear only at night.

    If you study the animal life, you'll find the main use of coloring is to protect themselves. Bears, lions and other animals move quietly through forests. They cannot be easily seen by hunters (猎人). This is because they have the colors much like the trees.

    Have you ever noticed an even stranger act? A kind of fish in the sea can send out a kind of very black liquid (液体)when it faces danger. While the liquid spreads over (散开), its enemies (敌人)cannot find it. And it immediately swims away. So it has lived up to now though it is not strong at all.

    When you look up into the night sky, you can see the moon. But do you know that you're only seeing one side of the moon? The other side, also known as the far side of the moon, has long been a secret to us. But now, we have a chance to see what's on the far side.

    On January 3rd, China's Chang'e 4 probe(探测器) landed on the far side of the moon. It is the first probe in history to land there.

    Chang'e 4 probe has already done a lot of things on the moon. One of its jobs is to grow plants. Chang'e 4 probe took six living things to the moon. Such as cotton, potatoes and fruit flies(果蝇). The cotton has already started growing. This is the first time humans have grown plants on the moon.

    Chang'e 4 probe also took a lot of pictures of the moon's far side. With these pictures, scientists will learn more about the moon.