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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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    Some researchers explain how most people form their social groups with people of their age. Especially, as children and teenagers, even adults, people make their friends based on proximity (邻近) more than anything else. Even in a college classroom, the students may not make friends with those who have similar personalities and interests. It's the people they really sit next to. Clearly, who stands to you has the greatest influence on you. As Jim Rohn has widely said. "You are average (平均) of five people you spend the most little with."

    Over the past ten months, I've paid Ryan, it Famous writer of several bestselling books, to help with the book I'm writing. Working with him has shown me just how low my standards for my work are. For example, every time I send him a drab (草稿), he shows me how it could     be 10 times better, and he holds me to that standard.

      ▲   It's because that I don't know what I don't know. Working with Ryan has made me realize what is possible and what it takes to create something powerful.

    Like Ryan, my business partner Richard has wonderful ideas and far different experience than I have. He has written 36 New York Times Bestsellers. He's been speaking and doing events for 20 years. Richard always performs at high levels, and he is also very strict with me because my performance is a reflection (反映) on him. It's not a bad thing because it creates high pressure (压力) to help me make great progress in organizing author training.

    In a word, you need to stay with those people who can help you realize your level and potential. Staying with people who have higher standards is the fastest way for you to change. If you don't change your environment, your progress will be very slow. Who you stay with has huge importance. You can't ignore this.

    Many environmental groups are warning that oceans of the world are in great danger. In the past 50 years, the number of water with zero oxygen(氧气) in the open ocean has increased more than four times. In the near coast water bodies, including the river mouth and seas, low-oxygen areas have increased more than 10 times since 1950.Scientists discover that oxygen continues dropping ever outside these zones as the Earth warms. To stop the drop, the world needs to control in both climate change and nutrient(养分) pollution.

    Oxygen is a must to life in the oceans. The drop in ocean oxygen is among the most serious effects of human activities on the Earth's environment.

    This is the first time for the scientists to take such a deep look at the causes, results and solutions to low oxygen worldwide, in both the open ocean and the near coast waters. About half of the oxygen on Earth comes from the ocean. However, mixed effects of nutrient loading and climate change are greatly increasing the number and size of "dead zones" in the open ocean and the near coast waters, where oxygen is too low to support most sea life.

    In the areas traditionally called "dead zones", like those in Chesapeake Bay and the Gulf of Mexico, oxygen drops to levels so low that many animals have trouble in breathing and die. As fishes run away from these zones, their living areas become smaller and smaller. But the problem goes far beyond "dead zones". Even smaller oxygen drops can hold up the growth in animals and lead to disease or even death. Low oxygen also can cause the release of dangerous chemicals. Although a few animals can grow well in dead zones, overall biodiversity(多样性)falls.