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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    Have you ever had dreams about building a robot? Or putting together a spaceship? Or even seeing your face made out of chocolate? Done. All you need is a 3-D printer.

    The possibilities of 3-D printing seem endless(无穷尽的）.All the user has to do is to design an object on the computer and choose a material to print in. The printers print in hundreds of different materials including glass, sugar and even skin! When the user presses(按）“print", the 3-D printer spreads the materials layer(层）by layer and like magic the object is produced.

    The first 3-D printer was invented in 1986 by an American, Charles Hull. But 3-D printing has only become cheap enough recently for most people to use. Designers now use 3-D printing to create unusual things. The Dutch artist Dirk Vander Kooj prints furniture made from old fridges. And doctors have used 3-D printing to print human body parts! The Telegraph reported in February that scientists from Cornell Medical College even printed a man-made ear.

    But like a lot of new technologies, if 3-D printing gets into the wrong hands, it can be dangerous.

    In 2011 a group of four men in the US used 3-D printing to produce ATM skimmers(提款机盗刷器).These were placed on an ATM and stole over $400,000 from users of the ATM. It is terrible to think that criminals like them might one day use a 3-D printer to print a gun.

    But for better or for worse, 3-D printing has been put into use. In a few years, you'll probably be wondering how you could ever live without your 3-D printer!

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    Is your TV connected to the Internet? What about your chair, or your fridge? Probably they are not. But in the future, most things in your home may be connected, thanks to the so-called "Internet of things".

    The Internet of things may be coming sooner than you think. Earlier this year, Samsung CEO spent a lot of time talking about the Internet things. He said that three years from now, every Samsung product will be part of the Internet of things, no matter whether it's a remote control or a washing machine.

    So, how do household objects that are part of the Internet of things work? Well, think of a common chair. When connected to the Internet, the chair warms up when it knows the user has just walked into the room and is feeling cold.

    An Internet-connected camera could help people feel safer in their homes. It can know people's faces and has an infrared sensor（红外传感器）, so even if it's dark it can see when someone passes by and send you a message on your smart-phone to let you know who's there. If the person is someone you don't know, it can tell you that, too.

    But according to MIT Technology Review, whether companies are connecting dog food bowls or safety systems to the Internet, there may be some problems. For example, many early connected-home objects don't have much built-in security, which means they could be hacked（攻击）. Moreover, it could be difficult to get these new machines to work together especially when they are made by different companies. To fight this, many companies have joined the Open Interconnect Consortium, which had 45 members by late 2015.

    So, picture this: you enter your home. The temperature changes to make you feel comfortable. Your favorite music starts playing for you. Do you think that this would be a good thing? It may happen sooner than you think.

    Do stars only appear at night? The answer is no .Venus （金星） is the one and only star that can be seen in the daytime. It shone at its brightest in the night sky on February 17^th, 2017.

    Venus is the second planet from the sun in our solar system. It is the second brightest natural object, behind Earth's moon, in the night sky. Why is it so bright?

    First of all, Venus is the closest planet to Earth. It is also covered by highly reflective （反射的）clouds, which can reflect about 70 percent of the sunlight striking（照射） it, almost twice as much as Earth does.

    Some called 2017 the year of Venus, because the planet is at its brightest when it goes further away from the sun, and nearer to Earth. The brightest moment happened once in February, and happened again, during daylight, on April 30^th.

    If Venus is so bright and close to us, isn't it a better choice for human exploration than Mars? It is closer to Earth than Mars and it's closer to Earth in size. The closer distance to the sun means solar power would be easier to generate （产生） as well.

    However, with a temperature of about 465℃on the surface, Venus is the hottest planet in our solar system!

    But scientists never give up. Recently, a team of NASA and Russian scientists created new computer equipment that can stand the temperature of 480℃. It can work under Venus-like conditions for almost 22 days.

    The next step, according to the scientists, is to send a probe（探测器）to Venus by 2025.

    Many people thought a computer wasn't supposed to be able to beat a top master at the ancient Chinese game, Weiqi, for at least another 10 years. But AlphaGo, an artificially intelligent system (人工智能系统) designed by Google, made it. It easily beat Lee Sedol last year, one of the best players in the world. It challenged the world's top players to show how much progress it had made over the past few years.

    In late May, 2017, AlphaGo appeared in China and played against 19-year-old Ke Jie in Wuzhen, China. He is No. 1 player now in the world. However, the result wasn't out of people's expectation. He lost the match. Though Ke Jie tried his best and he once saw the victory just a step away, he lost his best chance when he became excited.

    At the press conference (新闻发布会) after the match, Ke Jie was interviewed by the reporters. He said he had realized how powerful AlphaGo was, and it was getting perfect. When a Chinese reporter asked him in English, the reporter spoke so fast that the interpreter (口译员) couldn't catch him. Ke Jie got kind of angry and told him that it was unnecessary for two Chinese to speak in English. The reporter apologized to him and offered to ask him for a coffee.

    The cat and mouse game is over, but the challenge between man and robots will still go on.