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.

C

Why Are They Left-handed（左撇的）?

What do Napoleon, Clinton and Wang Nan have in common(共同的)? They are all left-handed. Today about 15% of the number of people is 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 controls the right half of the body.

    So right-handed people have a strong left brain, and left-handed 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, maths 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 your love of art, colour and music. It is also good at recognizing(认出) faces. This does not mean(意思是) that all artists are left-handed and all accountants(会计师) are right-handed. Some right-handed have a strong right brain, and some left-handed have a strong left brain.

    Many people are trying to save the earth with special days like "Meatout Day", "Earth Day" and "Buy Nothing Day".

    "Meatout Day" is on March 20. Many people around the world don't eat any meat for one day. In this way, they'll get healthier and reduce greenhouse gases (减少温室气体).

    "Earth Day" is on April 22nd. Many people all over the world try to do something green on this day. In Italy, people don't use plastic bags. In Canada and Norway, people ride bicycles and don't use their cars. In the USA, people dress up like plants and animals to dance in Times Square, New York.

    "Buy Nothing Day" is usually on the fourth Friday in November. On this day many people don't buy anything. "Buy nothing" means "make no rubbish". When you make less rubbish, you can make a cleaner earth.

    Do you want to join them? Then you can remember these special days and do something green.

    Some people claim they" never forget a face". But what does that saying mean? Is there really no limit to the number of faces a person can remember? A new study at the University of York in England has found that, on average, people can remember as many as 5,000 faces.

    The study is the first time that scientists have been able to put a number to the abilities of humans to recognize faces. The research team tested people on how many faces they could remember from their personal lives and in the media. They also tested them to see how many famous faces they recognized. Rob Jenkins works in the psychology department at the University of York. He said the researchers' study centered on the number of faces people actually know. He said the researchers were not able to discover whether there is a limit on how many faces the brain can handle.

    In the study, people spent one hour writing down as many faces from their personal lives as possible. At first, they found it easy to come up with many faces. But by the end of the hour, they found it harder to think of new ones. Their change in speed let the researchers estimate when they would have run out of faces completely.

    The results showed that these people knew between 1,000 and 10,000 faces. Jenkins explained that some people may have a natural ability for remembering faces." There are differences in how much attention people pay to faces and how well they process the information," he said. Jenkins also said it could be because of different social environments. Some people may have grown up in more populated places. Therefore, they may have had more social contact throughout their lives.

    The people in the study included 25 men and women between 18 and 61 years old. Researchers think age may be an interesting area for further research. "It would be interesting to see whether there is a peak age for the number of faces we know", Jenkins said. He said it is possible that we gather more faces throughout our lifetime. But, he added, there also may be an age at which we start to find it harder to remember all of those faces.

    The study suggests our facial recognition abilities enable us to deal with the many different faces we see on the screens, as well as those we know, like family and friends. Today, facial recognition technology is used in many ways, including by law enforcement agencies to prevent crime and violence. Governments use it to keep secret areas secure and, in extreme cases, control populations. .Even Facebook uses facial recognition. For example, when you "tag" or name a friend, Facebook technology may recognize the person's face from a different picture you had shared before.