Now lots of teenagers like smoking. It's a big problem. Some of them smoke, just for fun and some think smoking looks cool. Others smoke because there are many people around them that smoke.
    As we all know, smoking is harmful, especially to students. Some teenagers even steal money so that they can buy cigarettes. Besides, smoking does harm to brains and it can influence studies. Finally, it is bad for health because it can cause diseases.
    Therefore, we should protect ourselves from smoking. First, we should learn more about the danger of smoking. Second, we should keep away from people who smoke.

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    On a very hot day，it can be hard to know what to do to feel good．If we run around，we may feel dizzy and sick to our stomachs．This is because our body can't get rid of the extra heat．However，if we just sit and do nothing，we may feel restless and bored．Are there things we can do to feel good when we are hot? Yes! Playing in water is one way to feel cooler．Of course，people with a pool，river，lake or ocean nearby can play in the water very conveniently．People don't have these can still play in water too．Taking a cool bath or shower can feel good on a hot day．On hot days，you can lose two gallons(加仑)of water in one day，so many doctors agree that you should try to drink at least 16 glasses of water to keep the water balance in your body． Mixing a little juice into your water is a good way to help you drink plenty of water．The food we eat also makes a difference in how we feel in the heat．Cold foods，such as ice cream and drinks with some ice can cool down our bodies．Fruits and vegetables are easy for the body and refreshing．Plan a healthy menu for a hot day．

    There is a popular belief that goldfish only have a three-second memory. But a 15-year-old schoolboy from Adelaide has just finished an experiment to tell us that it is not true. He shows everybody that the goldfish is smarter than we think.

    "I don't believe that they had a three-second memory because animals need their memory, so they build up over time a knowledge of where the food is," said Rory Stokes, a student at the Australian Science and Mathematics School.

    He did the experiment in a small tank(鱼缸)of goldfish. "I decided to get a bit of red Logo and just feed them next to that. Every day I'd put it in and spread food around it." He said.

    "At first they were a bit scared of it, but by the end of the three weeks, they were actually almost coming before I put the food in."

    After leaving the fish alone for a week, Rory placed the red Logo block in the tank again.

    "They remembered perfectly well," he said.

    "They actually had a time faster than the average(平均)of the three feeds before I left."

    The goldfish showed that they not only could store information, but also had the ability to get it back at a later date.

    Culum Brown, a researcher at Sydney′s Macquarie University, has studied fish behavior for more than ten years.

    He says his studies of Australian native fish show fish are smart animals that know how to avoid enemies and catch food like any other animal.

    "The thing that I really liked about Rory′s experiment is that he not only got that classical conditioning going but the fact that he could get thorn next just to that specific coloured marker. I thought it was really good." He said.

    Have you ever had trouble sleeping in a new place? Lots of people do. And now researchers from Brown University in Rhode Island think they know why. They found that one-half of the brain "remains more awake" than the other half when people are trying to sleep in a new place.

    The sleep findings were reported in Current Biology by Brown University. In their report, the researchers said many people report that they have a harder time sleeping the first night at a hotel or other places outside their home. They call it "first-night influence". "In Japan they say, 'If you change your bed, you can't sleep,'" said Yuka Sasaki, one of the report's writers. "You don't sleep very well in a new place. We all know about it."

    The researchers measured brain waves (测量脑波) for 35 volunteers over two nights in a laboratory. The two nights were a week apart(间隔).They found during the first night the left half of the brain was more active than the right half. This was during the first deep-sleep period, the researchers said.

    Sasaki said a lot of questions remain.

    Researchers did not keep measuring brain waves all night long. So, they don't know if the left half keeps "watch" all night, or whether it" works in shifts (轮换) with the right half later in the night" .They also do not know why the brain activity, at least during the first period of deep sleep, is always on the left half.

    For some, this research may be calming. It is good to know that our brain is "looking out for us" in a new place. But it may not help with sleep. That brain activity, at least according to this new research, makes it harder to get the sleep people need to wake up well rested in the morning.

    Have you ever dreamed about sending a letter to yourself or your friends in the future? While express mail(快递) is a fast way to send your letters, there is another type of mail appearing in China as a new business—future mail.

    "The letter should be sent next Mother's Day and not a day earlier!" Lin Xiaofan, a college student in Shanghai, tells one of the companies offering the service.

    Lin Xiaofan wrote the letter to her mother nearly a year earlier to express her love to her mother for next Mother's Day.

    "Offering this service makes people slow down and lets them understand the meaning of 'time' in another way," said Zheng Zhimin, manager at a "future mail" company. Zheng thinks "future mail" letters help remind us of care, friendship and love.

    While "future mail" is becoming more and more popular, some people are wondering what will happen if the postal address changes or if the company goes broken before the letters arrive.

    Zheng said customers are glad to sign a contract(签订合同) to make sure that they can be compensated if their letters are lost or damaged.

    Most of the customers are college students and young white-collar(白领) workers. Psychologists (心理学家) said that young Chinese might have a new way to express their feelings through this service. Most people put their hopes and wishes in the letter so that they can experience the connection(联系) between the past and the present when they receive the letter.