A recently study found people's lives are made shorter in North China. It is showed the life expectancy(平均寿命) had been cut down by 5.5 years there. Researchers think that the heavy air pollution in China should be to blame. It's really the truth. Our government has already done something. However, it doesn't seem to work so well.

    “Air pollution in China is doing harm to people's health. The harm is much more serious than we can imagine,” said Chen Yuyu of Beijing University, one of researchers of this study.

    Dirty air brings serious problems in North China. In January this year, the air pollution was worse than that in other places. That was caused by rising temperature and waste gas from coal heating.

    Chinese government should strongly fight against air pollution. They should think of more proper ways to deal with the problem. People should be encouraged to take buses, ride bicycles or walk, instead of driving cars. The factories that pollute heavily should be closed.

    “We need to improve our environment, although it might be expensive. Protecting our environment means protecting ourselves,” Li Hongbin, another researcher of the study said.

    When you watch TV and play video games you make global warming(全球变暖) worse! To make electricity, fossil fuels(矿物燃料) are burned in big factories. But burning fossil fuels also makes greenhouse gases. This means that every time you use electricity you help make global warming worse!

    Cars are also making global warming worse. They burn fossil fuels in their engines, and send lots of greenhouse gases into the air.

    So what can we do to stop global warming?

    Try to use less electricity. First, turn off lights, your television, and your computer when you stop using them，You could also try to watch less TV. But you may find it hard to do these! Second, plant trees. Not only is it a fun thing to do, but it is also a great way to lower the number of greenhouse gases in the air. Trees take carbon dioxide(二氧化碳) out of the air when they grow. Last, don't throw away your rubbish, but try to recycle it. Because if rubbish is not recycled, it rots(腐烂) and makes a greenhouse gas called methane(甲烷). So try to recycle cans, bottles, plastic bags and newspapers. It'll make you feel great! And it'll help the Earth.

    A hundred years ago, most people thought that human beings would never fly. And the idea of flying seemed crazy and dangerous. But as a new world full of new inventions（发明物）came, everyone was trying to break the old thoughts. So many inventors, like Orville and Wilbur Wright, tried to make a flying thing.

    Most plane inventors at that time were impulsive. They would think of an idea, make a plane as quickly as they could, and then try to fly it as soon as possible. All of them had the same result they took their planes home and they had no idea why they didn't work.

    However, the Wright brothers were much smarter inventors. They tested their ideas in smaller or safer ones before making a real plane. For example, the Wright brothers made a wind tunnel(隧道)to compare(比较)wing shape ideas. They also flew lots of kites to test their ideas. They studied the way birds fly through the air and tried to learn something from it when making their models. Finally, the Wright brothers felt they were ready to test their planes, but they needed to find the right place. They knew the right place to test their planes after writing to the US Weather Bureau for help. At last on December 17th, 1903, Orville and Wilbur tested the plane and they made it.

    The plane flied for twelve seconds and it traveled just 120 feet, but Orville and Wilbur were very happy. Their plane really worked! By the end of the day, both brothers had great successful flights(飞行), with Wilbur having a record of 852 feet in 59 seconds.

    Try to imagine a life without a memory. It would be impossible. You couldn't use a language, because you wouldn't remember the words. You couldn't understand a film, because you need to hold the first part of the story in your mind in order to understand the later parts. You wouldn't be able to recognize anyone - even members of your own family. You would live in a present forever. You would have no past and you wouldn't be able to imagine a future.

    Human beings have amazing memories. Besides all our memories about our own lives, we can recall (回忆) between 20,000 and 100,000 words in our own language as well as possibly thousands more in a foreign language. We have all kinds of information about different subjects such as history, science, and geography, and we have many skills such as driving a car or playing a musical instrument. All these things depend on our memory.

    How well you remember things depends on many different factors. Firstly, some people have better memories than others, in just the same way as some people are taller than others. Secondly, research shows that, you can store different things in different parts of the brain. Ideas, words, and numbers are stored in the left—hand side, while the right-hand side remembers pictures, sounds, and smells. In most people, one side of the brain is more developed than the other, and this may explain why some people can remember people's faces easily, but can't remember their names.

    The air pollution was so bad in Harbin, in China, on October 21, 2013 that the city had to close roads and schools, and cancel hundreds of flights from its airport.

    News reports said the smog (a mixture of smoke and fog) was so thick that people couldn't see more than 10 or 20 metres in front of them.

    It is also said that people could not even see the person standing next to them. The city's website said: "You can't see your own fingers in front of you."

    The local people said there was a "burning" smell in the air. Many people covered their noses and mouths with scarves or masks.

    The pollution was caused on several factors including: farmers burning off old corn stalks and crop stubble; coal-fired heating systems; and low winds that allowed the smoke to remain over the city.

    The smog had been building up for several days. It became worse when the city turned on the public heating system, which uses coal to heat millions of homes and offices in the city.

    Harbin has a population of more than 10 million people. It lies in northeastern China, where cold winter weather can last up to six months. The main fuel there is coal, because it is cheaper than other types of fuel.

    Air pollution from burning coal can cause health problems like heart disease. During the smog crisis* in Harbin, the number of people taken to the hospital with breathing problems was 30% higher than usual.

    The city government is trying to reduce its use of coal by adding more insulation and better roofs and windows to buildings to reduce heating needs. It has also used cleaner fuel for cars and factories.