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    There is good and bad news about the number of trees on out planet. The good news is that there are seven times more trees for everyone than we thought.

    A few years ago, scientists believed that the world bad 400 billion（十亿）trees. However, a new study from Yale University shows that there are around three trillion（万亿）trees. Thatmeans a three followed by 12 zeroes. That means there are about 420 trees for everyone in the world today.

    The bad news is that thousands of years ago, the earth had six trillion trees. Humans cut in half the number of trees on the planet. Take Europe for example, it was a large forest thousands of years ago. Now much of it is cities and towns. And another 15 billion trees are lost each year.

    Dr. Thomas Crowther is one of the scientists from Yale University. He said the new number of trees from their study would change nothing. " The study only shows we need to do more to protect our forests." He said.

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    The koala is unique (独特的) to Australia and is an important symbol of the country. The koala is found in open eucalypt (桉树) forests in south-east Queensland. Even if it is called koala bear, this animal has nothing to do with the actual bear. Koalas have thick fur and large cars.

    Their broad, flat nose makes them look cute, similar to teddy bears. In fact koalas aren't cute. They have sharp teeth and very sharp claws (爪)! Koalas are marsupials (有袋类). This means the mother carries her baby in a pocket while it develops, similar to a kangaroo. The baby koala lives in its mother's pocket for the first six months of its life.

    The name “koala” comes from a native Australian word that means “no drink”. The koalas get almost all their water from the eucalyptus leaves they eat. That's where they get their food too.

    Koalas eat only eucalyptus leaves. The eucalyptus trees are where the koalas live, it's also where they sleep. Koalas sleep about nineteen hours a day!

    Why do they sleep so much? Some people think it's because they're lazy. But koalas aren't lazy. They sleep so much because there isn't much nutrition (营养) in eucalyptus leaves. Koalas store hardly any fat, so they must save their energy. One way to do this is to move slowly and sleep a lot. After a day of sleeping they like to move around and eat just after sunset. They live alone most of the time. Koalas are very protective of their trees. If a koala sees another koala eating in its favorite tree, it might tell the other koala to leave by “barking” at it. Koalas do “talk” to each other.

    Besides barks, the males make a deep grunting (呼噜的) sound.

    The mothers and babies talk in soft clicking sounds. If they get scared they may scream like a baby. The koala is also an excellent swimmer.

    They are able to cross rivers to escape from heavy flooding (泛滥).

    As the Internet is developing fast，more and more new words and phrases have been created in Chinese. Here are some examples.

    One of the most popular words is Dianzan，which is often used when you quite agree with someone. Another example is Renxing.

    When you say somebody is Renxing，you mean that they will do whatever they like. The phrase Miaosha first came from online shopping，which means you can complete your shopping orders before others. But now it's widely used when you achieve your purpose in a very short time. If you describe somebody as a Tuhao，you mean that he is very rich.

    You can find lots of such new Chinese words. Keep learning and you'll know more about Chinese culture.

    Today many people like growing plants at home because the plants help make the indoor environment beautiful and healthy. However, sometimes people may be too busy to remember to water their plants. If you have the same problem, don't worry. Designer Alastair Crompton can help you solve the problem with his amazing product-Plant Pod. It can water itself without any help.

    The Plant Pod is a self-watering container (容器) for small to medium-sized plants inside the house. Alastair Crompton makes it use a very simple process to provide the plant with the water it needs every day. With a Plant Pod, people no longer need to worry about how much water is perfect for their plants to grow. The water in the Plant Pod is enough to last for at least two weeks. So if people are away from home on a short holiday, they don't need to ask their relatives or neighbours to look after their plants. Won't it be great to see your plants welcome you when you are back home after one or two weeks?

    Height is just one of the thousands of features that your genes(基因) decide. In fact, because you have two parents, your genes provide you a height that usually lands somewhere between the height of each parent. If both your parents are tall, then most probably you will be tall, too. But if you have questions about how tall you're going to be, ask your doctor if he or she can help you find it out.

    But genes don't decide everything. For example, eating an unhealthy diet can keep you from growing to your full potential(潜力). Getting plenty of sleep and enough exercise will help you grow to the expected height.

    No doubt you're wondering how fast you should grow. There's no perfect or right answer. Generally speaking, kids grow about two inches(six centimeters) a year between age 3 and the time when they start puberty(青春期).

    Your doctor will know how your growth has been going over the years, how you've been growing up to this point, and what other changes your body may be going through.

    Don't be scared if you seem to have grown a lot in a very short time. Everyone has a growth spurt(高峰) during puberty. The age for starting puberty is about 10 for girls and about 11 for boys. But it can be earlier or later-between 7 and 13 for girls and between 9 and 15 for boys.

    You'll usually begin to notice that you're growing faster about a year or so after your body starts to show the first changes of puberty.