Canada Geese are large blue and white birds. When autumn comes, they have to fly south where the weather is warmer. The winters are so cold in Canada that the birds will die if they stay there.

Last spring, Bill Lishman found sixteen young Canada Geese on his farm. They had lost their parents. Bill thought, "These young birds won't know what to do in the autumn." He had a small plane and he decided to teach the birds to fly by following him. All through the summer, he went on short trips in his plane and the young geese flew after him.

When the cold weather arrived in the autumn, Bill flew to Virginia in the United States——600 miles South of his home in Canada. The geese followed him all the way. Bill left the geese in Virginia and he returned home.

    This spring, Bill was waiting for the birds to come back. They didn't arrive, so Bill flew to Virginia to get them. He looked for them for two weeks but he couldn't find them. When he arrived back home, he found the geese waiting for him. They had found their way home without him!

( No more than 4 words)

You may know a lot about smartphones. But what about smart cities?

Imagine living your life like this: When you wake up in the morning, you say "Open the window" to the computer and it opens the window. The sunshine is shining and the birds are singing. Then you finish breakfast and sit in front of your desk and begin to have classes through the Internet. With the help of building a smart city, this may become true one day.

A smart city uses digital technologies(数字科技）such as the Internet to improve city planning, save resources(资源) and make our lives easier. For example, people live in smart cities, where there is Internet almost everywhere. They can do many things at home, such as booking train tickets, paying water bills and shopping online. What a convenient life it is!

Now China is making some cities smarter. For example, Guiyang is going to build free Wi-Fi in the whole city. Tianjin plans to start a smart city program to solve traffic problems. Guangzhou is creating a smart city, so everyone in the city should play a role in creating a smart city.

    I'm the engine that keeps you working, and I'm here to share some of my secrets.

    I have 100 billion nerve cells (神经细胞), so you need to consider before you blame (责怪) me for not being so fast enough. It's not really my fault: information travels through me too fast and sometimes I can't keep all of it.

    The Internet is making me weak. A study found that you've been relying more on the Internet. That means I'm going to forget more over time. Scientists have been worried that our ability to think is being lost.

    In general, I'm about ten percent larger in men than women. It doesn't make men smarter. It just lets me control their different bodies. Actually, it's more common for women to get angry, but men can't focus on a thing well. They usually have language difficulties.

    Your mobile phone scares me. A new study showed that more than one hour of mobile phone use can get me in trouble. Mobile phone radiation (辐射) might cause me to be in a worse situation.

    Some parts of me never sleep. It's important for you to get a good night's sleep. Sleep helps to improve memories. In fact, when you are asleep, some parts of me are still working hard on my duty.

    Besides, laughter is really the best medicine for me. So remember to laugh more for my better situation.

    There are millions of stars and planets in space. What's the difference between stars and planets? Stars can give out heat and light, but planets cannot.

    The sun is one of the stars. Some planets are balls of rock and some are balls of gas. We live on the planet earth. The earth spins around once every day to give us day and night. The earth goes around the sun once every year to give us different seasons.

    There are eight planets moving around the sun. We call the family of the sun and its planets the solar system. Mercury is the nearest to the sun, so it is very hot. It is the smallest planet. Venus is very bright and hot. It is the nearest to the earth. Mars is covered with orange-red desi and rocks, so it looks like a red star in the sky. It has seasons like the earth. Jupiter has more than 16 moons （卫星）and it is the biggest and heaviest planet. Saturn has more than 22 moons. The other planets, such as Uranus and Neptune, are all very far from the sun and very cold. We need a telescope（望远镜）to see them.