When you're not at home, many worries may start to crowd your mind. Did I turn the coffee maker off? Did I lock the door? Are the kids doing their homework or watching television? With a smart home, you can quiet all of these worries.

　　　A smart home is a home with a communication network. This network connects devices(装置),such as lights and TV sets, and allows them to be controlled from far away through electrical wiring, mobile phone communication or WiFi over the internet.

　　　More and more people may start to consider owning a smart home, because it makes life much more convenient. It can help keep your room at a certain temperature. It can record what happens inside the home and send the video to your phone. When you are on vacation abroad, you can use a smart home controller to switch on or off the electricity when necessary. Some smart homes can receive a visitor, allowing him to come in and offering him a drink. They can even feed the cat and water the plants.

　　　Besides, smart homes are easy to fix. Most smart home technology and devices are wireless and can be set up with a minimum of tools, using only the guiding information. When a problem appears, you can deal with it yourself without paying a professional.

　　　However, for home-users, the smart home technology is far from perfect. It can be rather expensive to own the technology and the devices. Also, because the smart home system(系统)allow its owner to get home information from anywhere, it leaves the home easy to be attacked by hackers(黑客),who may secretly use or change the information in the system.

　　　Now, many scientists are excited at the future of smart home technology. Imagine being able to get fashion advice from your mirror, or receive food shopping suggestions from your refrigerator. While there are others who worry that those smart devices will make people lazier and lonelier. Whatever it is, one thing is for sure—smart home technology will change the way we live and work.

    What will our world be like in 2020 We aren't quite sure, but it's interesting to make some predictions.

    Languages

    English should still be the most popular language, but Chinese should be the second. Now, many foreign people are studying Chinese as their second language.

    Water

    Water will become as expensive as oil because many rivers will disappear. We will have to save water and pay more for clean water.

     Education

     More students will study online. Students from all over the world may study together on the Internet.

Americans love cars. They go everywhere in them. 85% of people in the US go to and form work by car. And most adults have driving licenses. Why does this car culture exist?

How it started

America's love of cars started after the war when soldiers returned home from World War Π to rebuild their lives. They borrowed money from the government to buy houses and cars which became the symbols of status（地位）. The more money they had, the bigger their cars were.

Making of roads

During the war, President Eisenhower noticed what good roads Germany had. He decided to build new four-lane（四车道）roads in America. He said is something happened suddenly, the two-lane roads wouldn't be able to carry all the cars that would suddenly leave the cities. Car and oil companies liked his idea and building started.

Car lovers

Not just teenagers are crazy about cars. Some Americans love their cars so much that they paint their cars beautifully. These are called Art Cars. Every April there is an activity in Houston, Texas, where they show their cars.

Pollution

Cars have polluted the environment. American President Bush refused a worldwide law that is against pollution. Many countries were angry about it. Bush said he had to think of the American economy（经济）and all the American people that make money from cars. Factories say they want to make cars that pollute less. But others say making cars that pollute less will never be as good as having fewer cars.

阅读理解

When settlers (移民）came to America during the 1600s, they were surprised to find so many trees. Some trees were so huge that a large man could not put his arms around them. Those trees helped the settlers a lot. They were glad and thankful to have these trees. They used them to build houses and make fire. From the wood of the trees, they made furniture, tools and so on.

Most people thought the forests would last forever. However, by 1800, America had its first wood shortage (短缺). How did it happen? People had not known that trees were being cut down faster than new ones could grow.

Some American people made trips to foreign countries. There they saw destroyed forests and learnt the importance of protecting forests. They came back to the United States and warned that if Americans didn't use trees more carefully and wisely, someday the forests would all be gone. However, people were not ready to listen. Years went by, and America's forests kept disappearing. It made some people really worried. But they did nothing.

Finally, J. Sterling Morton, the man who is remembered as the father of Arbor Day (过节), got people to listen. He named a Tree-Planting Day, or Arbor Day. He worked hard to make Arbor Day a national holiday. On that day, people usually plant a lot of trees.

Today, millions of trees have been planted in the United States because of Arbor Day. Arbor Day is such a good idea that many other countries now also have Arbor Day. Many, many trees are being planted all over the world because of J. Sterling Morton's work.

    What is a museum? A museum is a good place to keep old and beautiful things. A museum may be a place to learn about science and a place to find out about art or people or animals.

    What is inside a museum? Some museums have old cars and airplanes. Many museums have pictures and statues(雕塑). Others have rocks and old bones (骨头). One museum even has a real old street inside. It has shops and people's statues doing business. It looks so real that one might feel that he was back to the old time.

    Many cities have museums. Some very small towns have museums, too. Indianapolis has a children's museum. Children do not have to pay (付款) to get in. Children often go to the museum. They like to look at the dinosaur (恐龙)bones. They see a white bear ten feet tall.

    On Saturdays, Indianapolis children can hear talks about animals and trees. They see movies. They take hikes. They even learn to make things there.

    Have you ever heard robot fish? Scientists will put some robot fish into the sea near Spain. These robot fish will help people to detect (探测) the pollution in the water. If the robot fish are able to finish their work successfully, the scientists hope to put them into rivers, lakes and seas around the world.

    The fish are about 1.5 meters long. There will be a detector in their bodies. They can find the sources (来源) of pollution in the water, and then the robot fish will eat part of it. Unlike other robots, they don't need to be controlled by people far away. The robot fish all have an eight-hour battery (电池). They can "swim" in the sea freely and send back information to people on the beach. After their batteries die, they will return by themselves.

    There are five robot fish altogether now. Each costs about 29,000 dollars. They are part of a three-year project between engineering company BMT Group and Essex University in southeastern England.

    "We invented the robot fish creatively. We hope them can find the changes in the sea water and report back the information," said Professor Hu of Essex University. His team is developing the fish.