Lately, people have entered the forests where chimpanzees (黑猩猩) live. The chimpanzees have been getting sick because of people's diseases. In addition, people are hunting chimpanzees. Their number is becoming smaller and smaller.

Chimpanzees live in the plains and forests of Africa. They eat many kinds of food, from plant leaves and seeds to insects and even other small animals. Chimpanzees' favourite food is fruit.

    Chimpanzees are very clever and they can use tools well. They can catch bugs using sticks, and break nuts using rocks.

    The world's forests are much smaller than they were before. Roads were built in deep forests, so people start to enter forests where chimpanzees live. That may lead to many problems. One problem for chimpanzees is that they can easily catch people's diseases and die. Chimpanzees are much closer to people than monkeys.

As it's easier for people to enter forests, they hunt more often. Young chimpanzees are caught to be pets or for scientific researches. The young ones are taken away from the forests, and the adults are killed. Chimpanzees are likely to disappear in the future.

    When the weather is hot, you go to a lake or an ocean. When you are near a lake or an ocean, you feel cool. Why? The sun makes the earth hot, but it can not make the water hot. Though the air over the earth becomes hot, the air over the water stays cool. The hot air over the earth goes up, then the cool air over the water moves in and takes the place of the hot air. When you are near a lake or an ocean, you feel the cool air when it moves in. You feel the wind and the wind makes you cool.

    Of course, scientists cannot answer all of our questions. If we ask "Why is the ocean full of salt?" scientists will say that the salt comes from rocks. When a rock gets very hot or very cool, it cracks (崩裂), and rain falls into the cracks. The rain then carries the salt into the earth and the rivers. The rivers carry the salt into the ocean. But then we ask "What happens to the salt in the ocean? The ocean does not get saltier every year." scientists are not sure about the answer to the question.

    We know a lot about our world. But there are still many answers that we do not have, and we are curious(好奇的).

    It is important for us to look after the Earth well. The Earth gives us a lot of things. We also give the Earth a lot, but some of the things are not good.

    In nature, when something dies, other animals and plants get food from it. Every animal or plant provides food for other animals or plants. However, animals can't get food from many of the things that we"give" the Earth. Animals and plants can't cat metal, plastic or glass. These things will stay in the ground for many, many, many years.

    Some rubbish is very dangerous for plants and animals. In some places, many animals live together. One animal makes food for many other animals. If we throw rubbish and chemicals into the water, the plankton（浮游生物）can die. If there isn't any plankton, many animals have nothing to eat.

    So what can we do? Don't leave any rubbish in the countryside! Don't make so much rubbish.

①A tidy desk helps you find things easily and is good for your study. But how can you keep your desk tidy?

②First, only put things you need on your desk. For old books, you can put them in the bookcase. Get a box for small things you don't need every day, and you can put your pens and pencils in a pencil box.

③Second, don't put food or drinks on your desk, because they can make your desk dirty. Go to the kitchen when you want to eat.

④Third, put important(重要的)things next to you. Then it is easy for you to get them.

⑤Fourth, clean your desk every day. If you do it every day, you can have a new day with a tidy room the next morning.