There are many kinds of animals that live in the forest, such as mice, rabbits, squirrels, bears.

    Animals in the forest depend on（依靠）one another for food. Many small forest animals, such as mice, eat green plants for food, and then larger animals eat them. This is called food chain. A food chain begins with the sun. The green plants in the forest use the sun's energy to make food for themselves. It's called photosynthesis(光合作用). Mice eat flowers and seeds that forest plants produce(生产).The mice get their energy from the plants, and the mice become food for a larger animal, such as the hunting hawk. So the energy from the sun passes from the plants to the mice to the hawk. A break（中断）in any part of this food chain means some animals may not have enough food to eat.

    The leaders （领导人） of 13 countries had a big meeting in St Petersburg, Russia from November 21 to 24, 2010.The meeting was about tigers. They talked about the ways to protect the animals in their countries. They agreed to spend more money protecting tigers and they wanted to double the number of tigers in the world before 2022.

    Tiger is one of the world's most endangered animals. The World Wildlife Fund （WWF） says, there are only about 100,000 wild tigers now. And the number is becoming smaller and smaller. 'If nothing happens, tigers will face disasters,' said WWF spokeswoman Marie von Zeipel.

Nine types of tigers lived 100 years ago, but now at least three of them have died out. ‘If people leave tigers alone and don't kill them, then the number of tigers will double in 10 years,' said Jean-Christoph Vie, a French tiger expert (专家).

    China is one of the 13 countries where tigers live. There are about 50 wild tigers in China now. They are the Bengal tigers in Tibet, Indochinese tigers in China's southwest, and Siberian tigers in the northeast. The South China tigers lived in southeast China many years ago but disappeared in the 1970s. Many experts think they have already died out.

    My house is made of wood, glass and stone. It is also made of software.

    If you come to visit, you'll probably be surprised when you come in. Someone will give you an electronic PIN to wear. This PIN tells the house who and where you are. The house uses this information to give you what you need. When it's dark outside, the PIN turns on the lights nearest you, and then turns them off as you walk away from them. Music moves with you too. If the house knows your favorite music, it plays it. The music seems to be everywhere, but in fact other people in the house hear different music or no music. If you get a telephone call, only the nearest telephone rings.

    Of course, you are also able to tell the house if you want something. There is a home control console (控制台), a small machine that turns things on and off around you.

    The PIN and the console are new ideas, but they are in fact like many things we have today. If you want to go to a movie, you need a ticket. If I give you my car keys, you can use my car. The car works for you because you have the keys. My house works for you because you wear the PIN or hold the console.

    I believe that several years from now on, most new homes will have the systems that I've put in my house. The systems will probably be even bigger and better than the ones I've put in today.

    I like to try new ideas. I know that some of my ideas will work better than others. But I hope that one day I will stop thinking of these systems as new, and ask myself instead, “How did I live without them?”

    On April 2, we said goodbye to Tiangong I, China's first space lab. According to the China Manned Space Agency (中国载人航天), Tiangong I re-entered the Earth's atmosphere (大气层) and some of its debris (碎片) fell into the South Pacific Ocean.

    There are many spacecraft (宇宙飞船) that are still in orbit(轨道) above the Earth. After finishing their trips, they will all re-enter the Earth's atmosphere like Tiangong I.

    There are two types of re-entries: controlled re-entry and uncontrolled re-entry.

    Some satellites and manned spacecraft come back to the Earth in a controlled re-entry. Experts calculate (计算) the path of the falling spacecraft and its speed. Thy can guide the spacecraft to fall in a chosen area.

    Some spacecraft may have problems while in space after a certain amount of time. These spacecraft come back in an uncontrolled re-entry. It is hard to tell when and where these spacecraft will fall until the last few hours. The US space station Skylab came back partially uncontrolled in 1979. Parts of the station fell in western Australia, but no one was hurt.

    During re-entry, most of the spacecraft will burn up while passing through the Earth's atmosphere. Only a small amount of the debris will reach the ground. The debris typically ends up falling into the ocean, China Daily reported.

    Many people have dogs at home as pets. If a dog is happy, then he may want to meet you or play with you. If he doesn't feel happy, then he would rather stay alone. But dogs can't talk. How can you tell how your dog is feeling? By his body language.

    If your dog's head and back are lowered, his ears are down and his eyes are narrowed, and his tail is between his legs, then he is fearful. You may touch him gently to comfort him. If your dog's ears are up, his eyes are bright, and he wags his tail rapidly (快速地), he is very happy. He may also hold his mouth open more or even pant (气喘) mildly. Then you can go and play with him freely. If he closes his mouth and looks serious as you get closer, then he has changed his mind. It is better to leave him alone until he comes to you. Remember, we are talking about dogs that you know. Be sure a parent is around to allow you to get close to the dog. Get away from strange dogs even if they seem friendly.

    The most important clue (线索) is the mouth. If the dog's mouth is closed, then he is most likely to be not relaxed or happy, and he does not want you to touch or play with him right now.

    Many of us enjoy watching animals in the world. But do you know they can teach us?

    Geese(雁), for example, teach a very good lesson about 1. In the fall, Canada geese fly to the warm south to 2 Canada's cold winter. They lift off in no order. Yet 3 they form a V shape, with one bird leading the group.

    This V shape allows geese to 4 energy. When the front bird moves its wings up and down, the resulting force of the air lifts the next one. This continues down the line. The bird 5 has the hardest job. When it gets6 , it moves behind, and another bird moves into the lead. By sharing the role, the group can travel great distances. Geese flying in a V shape can fly 70 per cent farther without 7 than birds flying alone. During the long flying journey, geese communicate with one another. They honk(鸣叫) to 8 the birds up front to keep up the speed. They also cheer each other up 9 working toward a common goal.

    What have we learned from the lovely geese's experience and skills?

    10 together! Whether it is our personal lives or our jobs, we need other people. We need the spirit of teamwork!