The sun is a huge, hot and bright star. It is important because without it there would be no life on the earth. The sun gives us light and heat.
All living things depend on the sun for their growth. Plants need light and heat to grow. They use the light from the sun to make food. But we human beings cannot make food by our own bodies from the sun. All the food we eat comes from plants in a food chain(链) . And the food chain starts with the sun . For example.
sun —→ potatoes  —→ chips
sun  —→ corn  —→ hens  —→ eggs
sun—→ wheat  —→ bread
     Animals need sunlight, too. Just like us, their food comes from plants in food chain, which begins with the sun. For example,
Sun → leaf → caterpilllar(毛虫) → bird
Sun → seaweed(海藻) → small fish → whale(鲸)
     With the help of sunlight, we can see things during the day. Even when the sky is cloudy, the sunlight is very strong and it shines through the clouds. If there was no sun, it would be dark all the time.

    A computer can get very hot when it works on a lot of programs. It can cost a lot to cool the computer. So some scientists want to know what would happen if the heat from the computer could be used.

    Large Internet companies such as Google and Microsoft have thousands of computers. As these computers deal with information， they produce lots of heat， so they need huge cooling systems. These systems send the heat into the air.

    A company in Holland thinks paying to make the computers work and then paying again to cool them are a waste of energy. So the company developed a special device—the e-Radiator.

    Boaz Leupe， head of the company， says that e-Radiator works as a heating system and saves money. He explains that the energy is used twice—once to heat the home and once to cool the computer and that the users don't have to pay to cool their computers.

    Five homeowners in Holland are testing the heating system in their homes.

    “We pay for the computer using， so， in that way， homeowners get heating for free.” Boaz says.

    Jan Visser is one of the homeowners. “If you use the computer more， the e-Radiator producers more heat，” he says， “It cannot provide enough heat if you don't use your computer often.” But he is ready to try it. It's a great help for his family.

    The company says e-Radiators produce heat temperatures of up to 55℃. It says the system could save its users about $440 a year.

    In recent years, there have been many breakthroughs in the AI (人工智能) field. Here, let us see four of the most interesting developments in AI in 2017.

    Technology is changing our ways of life. Robby Pepper is Italy's first robot gatekeeper. He can answer questions in Italian, English and German. He is placed at a hotel to help answer simple questions from visitors. A guest from Moldova, congratulated the robot on his skills. "He's like a real person. He's really good." She said. "He talked to me, and he shook my hand."

    Japan's Softbank Robotics created Robby. It can provide hotel guests with information they need, like where to find a restaurant and its hours of operation. The use of robots is growing in service industries like tourism. But they are expected to become more useful as better artificial intelligence, or AI, is developed.

    The International Federation of Robotics says about 79,000 professional service robots were sold last year. It expects up to 25 percent sales growth each year. There are many different kinds of artificial intelligence machines: learning robots, cleaning robots, medical robots and public relations robots.

    We have made some progress in the development of AI, but we still have a long way to go. Experts say people in the United States and Japan seem more welcoming to robots than people in Europe do. Shoppers at a store in Scotland got one robot, Softbank's Fabio Pepper, fired out Customers were not willing to talk to the robot. And a security robot in Washington DC made news last year when it rolled itself into a fountain*and could not get out.

    In Brescia, the Cayu car sore is using another Softbank Pepper robot to sell cars Named Cayuiki .the robot is programmed to give information on cars, playing games and collecting information. It is helping to bring in possible car buyers .But the head of the Cayu car store said, "To sell the cars, you still need human beings."

    Thousands of years ago, people didn't know that the Earth moved. They thought the sun really did move across the sky. The Greek god Helios was said to drive the sun across the sky with his chariot (战车). But now, the way people think has changed. Nowadays, it is the sun that drives a "chariot" around the sky.

    What do I mean by this? Well, quite simply, there is now a plane (or "chariot") that is powered by the sun. It has special parts on its wings. These parts absorb (吸收) power from the sun. They absorb so much power that the plane can still fly even at night. In Greek mythology (神话), Helios had to take a break at night. It seems we're finally even more powerful than the gods themselves.

    This plane is called Solar Impulse. It will fly across the US in May. This is very important for the future of the world.

    Why is solar energy (太阳能) important? Well, other kinds of energy are known to cause problems. If you live in China, you've probably noticed the pollution. This is caused by burning coal and gas to make energy. The heat and chemicals created by burning these things give us power. But if we use power from the sun, we don't have to burn anything and there will not be any pollution.

    Solar energy is not entirely ready yet. It needs to be improved. But the best thing about it is that, unlike coal and gas, it doesn't run out. The Solar Impulse plane could pretty much keep flying forever. Of course, the sun's light will eventually run out too one day, but not for another 5 billion years. That's a pretty long flight.