Smog(雾霾) is a big problem in many Chinese cities. But it seems that besides wearing a mask, few of us know what has caused the smog and what to do to beat it. Chai Jing, a former news hostess with China Central Television, discussed the questions in her documentary Under the Dome.

    The 103 - minute film was published on major Chinese video - sharing websites on Feb 28. In the film, Chai visits polluted places and talks to officials and scientists. She comes to the conclusion that burning too much coal and oil are the main causes of PM2.5 and smog.

    To make things worse, according to Chai, the coal and oil we are burning is of poor quality and don't meet the standards for environmental protection. Therefore they have produced more harmful gas to pollute the air.

    To solve the problem, Chai suggests that we should clean our coal and oil or replace them with cleaner energy such as natural gas. In her film, Chai also pointed out that ordinary people can do something to help control smog too. For example, we live a greener life by using more public traffic. Or if we see things that could harm the environment, we can try to stop it. In one scene from the film, Chai sees a dirt mound in a building site exposed in the air, and asks the person in charge to cover it. When she sees a restaurant cooking without any suitable filter facilities, she calls the hotline 12369. The restaurant installed the filter a week later.

    Chen Jining, the new minister of environmental protection, praised Chai. "This film encourages ordinary people to care about the environment. This is what we need in the future. "

    Have you ever stood beside the ocean and stared at the waves (波浪)? The way they move is changing! Nothing is more peaceful than watching the movement of water.

    Every ocean has waves. Unless you are lucky enough to live by the sea, though, you probably can't watch the waves very often. How would you like to have your own wave machine? Making one is easy and a lot of fun.

    Now that you have made your ocean, put your bottle on its side. Wait a minute. The water win be on the bottom. The oil and paint thinner mixture will be on the top. Now tip (倾斜) the bottle back and forth (反复来回) and watch the waves.

    What do Napoleon, Clinton and Wang Nan have in common? They are all left-handed.

Today about 15% of the people are left-handed. But why are people left-handed? The answer is the way the brain (大脑) works. The brain has two halves—the right half and the left half. The right half controls (控制) the left side of the body, and the left half controls the right side of the body. So right-handed people have a strong left brain, and the left –handed people have a strong right brain.

    The two halves of the brain are about the same size. But each side controls different things. The left side controls language, Math and logic (逻辑). When you remember new words, or when you put things in order, you use your left side.

    The right side of the brain controls color and music. It is also good at recognizing (认出)faces. This does not mean that all artists are left-handed and all accountants (会计师) are right-handed. Some right-handers have a strong right brain, and some left-handers have a strong left brain.

    Most of us know that Ikea is the world's biggest furniture company. However, did you know that it's also a pioneer in environmental protection?

    Ikea says it's working hard to improve the environment. The company has made huge efforts to cut the carbon emissions(碳排放)of its suppliers(供应商).Over the past five years, Ikea has helped its suppliers become 18 percent more energy-efficient. It managed to do so by bringing its suppliers together. The one that produces the least carbon emissions will be praised.

    Ikea has also invested(投资)heavily in clean energy. The company now operates more than 300 wind turbines(叶轮机)around the world. It has also set up nearly 750,000 solar panels(太阳能嵌板)on the roof of its stores. As a result, Ikea can produce 71 percent of the energy it uses, which are all from clean sources. In some countries，such a} Denmark and Finland，the company produces as much energy as it uses.

    Ikea has been buying forests as well. It owns nearly 750 square kilometers of forest.

    Last but not least, Ikea has tried changing customers' behavior(行为).It does so by improving product designs. In 2015, Ikea changed all of its lighting products into LED. This change alone, it says, has saved lots of electricity.