A recent 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（研究者）think that the heavy air pollution in China should be to blame(承担责任). 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（气体）from coal heating（燃煤）.

    Chinese government should strongly fight with 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.

Suggestions for Traveling

    Life in the future will be different from life today. Between then and now many changes will happen. But what will the changes be?

    The population is growing fast. There will be many people in the world and most of them will live longer than people live now.

    Computers will be much smaller and more useful, and there will be at least one in every room. And computer studies will be one of the most important subjects in schools then. People will work fewer hours than they do now and they will have more free time for sports, watching TV and travels. Travelling will be much cheaper and easier. And many more people will go to other countries for holidays.

    There will be changes in our food too. More land will be used for building new towns and houses for all the people. Then there will be less room for cows and sheep, so meat will be more expensive. Maybe no one will eat it every day. Instead they will eat more fruit and vegetables. Maybe people will be healthier. Work in the future will be different too. Robots will do dangerous and hard work. Because of this, many people will not have enough work to do. This will be a problem.

    Do you know the whales in the sea? There are many relatives(亲属) in the whale family and they always live together with whales.

    Few people know dolphins(海豚) are part of the whale family. Dolphins are not fish. They are mammals(哺乳动物). They breathe air, and they have babies and feed them with milk. Dolphins are famous for their wonderful shows. They can jump high out of the water and show turns in the air. These jumps give the dolphins time to breathe.

    Porpoises(鼠海豚) are also in the whale family and are quite like dolphins. But they are different in the size and shape of the mouth. The dolphin's mouth is long and thin, but the porpoise's is short and thick. Dolphins are also more talkative than porpoises. Dolphins make sounds to talk with each other under water. But porpoises do not do this. Both of them are smart and friendly to humans.

    Not all the members of the whale family are friendly. Big whales are much easier to be angry than smaller dolphins or porpoises. An angry whale can be dangerous. Perhaps this helped to create the story of Moby Dick that sank (使下沉) a ship and made all the people on it die in the sea.

Everybody dreams. But only some people remember their dreams. Our dreams often include all the senses —- smells, sounds, sights, tastes and things we touch .Sometimes we dream the same dream over and over again.

    Early in the twentieth century, two famous scientists developed their personal ideas about dreams. Austrian psychiatrist (奥地利心理学家) Sigmund Freud wrote a book called "The Interpretation (诠释) of Dreams" in 1900. Freud believed people often dream about things they want but can't have. Swiss (瑞士) psychiatrist Carl Jung worked closely with Freud for several years, but he believed dreams provide solutions to problems we face when we are awake.

    Other researchers are studying how dreaming helps our bodies work with problems and very sad emotions (感情). Robert Stickgold is a professor of psychiatry (心理学教授) at Harvard University in Massachusetts. He says that when we dream, the brain is trying to make sense of the world. He does not agree with Sigmund Freud that dreaming is the way we express our hidden feelings and wishes.

    Scientists believe it is important to keep researching dreams. Doctor Stickgold says it's more than one hundred years since Sigmund Freud wrote his important book about dreaming. Yet there is still no agreement on exactly how the brain works when we are dreaming or why we dream.

    When the Audet family turns on the lights at Blue Farm, they are using electricity that comes from cows- cow manure(粪肥).

    Cows produce a lot of waste. One cow can create 30 gallons of waste each day. Now imagine the output of over 1,000 cows at Blue Farm. That's really a big amount.

    When farmers clean their barns, they put the waste together，and spread some of it on their fields for fertilizer(肥料). But now places like Blue Farm have a new way of using cow waste. They use it to produce electricity.

    Here's how it works: A big machine moves back and forth cleaning the barn floor. "The cows are animals of habit; they get used to it,and just lift one foot and then another to let it go by. "says Marie Audet.

    The machine pushes the manure into a big 600-gallon tank like a small swimming pool. The tank is called a digester(化粪池) because what happens there is just like what happens inside a cow: Bacteria(细菌) get to work and continue to digest the manure.

    Methane gas(甲烷;沼气) in the atmosphere is known as a "greenhouse" gas because it keeps heat just like a greenhouse does, causing our planet to warm up. That's an environmental concern. But the digester has a good result. Its gas is kept and used to power electric generators(发电机).

    At Blue Farm, the generators make enough electricity to power 400 homes. The Audet family sells the extra electricity they can't use themselves.