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    There's a new frontier in 3D printing that's beginning to come into focus: food. Recent development has made possible machines that print, cook, and serve foods on a mass scale. And the industry isn't stopping there.

Food production

    With a 3D printer, a cook can print complicated chocolate sculptures and beautiful pieces for decoration on a wedding cake. Not everybody can do that — it takes years of experience, but a printer makes it easy. A restaurant in Spain uses a Foodini to "re-create forms and pieces" of food that are "exactly the same," freeing cooks to complete other tasks. In another restaurant, all of the dishes and desserts it serves are 3D-printed, rather than farm to table.

Sustainability(可持续性）

    The global population is expected to grow to 9.6 billion by 2050, and some analysts estimate that food production will need to be raised by 50 percent to maintain current levels. Sustainability is becoming a necessity. 3D food printing could probably contribute to the solution. Some experts believe printers could use hydrocolloids (水解胶体) from plentiful renewables like algae(藻类) and grass to replace the familiar ingredients(烹饪原料). 3D printing can reduce fuel use and emissions. Grocery stores of the future might stock "food" that lasts years on end, freeing up shelf space and reducing transportation and storage requirements.

Nutrition

    Future 3D food printers could make processed food healthier. Hod Lipson, a professor at Columbia University, said, "Food printing could allow consumers to print food with customized nutritional content, like vitamins. So instead of eating a piece of yesterday's bread from the supermarket, you'd eat something baked just for you on demand."

Challenges

    Despite recent advancements in 3D food printing, the industry has many challenges to overcome. Currently, most ingredients must be changed to a paste(糊状物) before a printer can use them, and the printing process is quite time-consuming, because ingredients interact with each other in very complex ways. On top of that, most of the 3D food printers now are restricted to dry ingredients, because meat and milk products may easily go bad. Some experts are skeptical about 3D food printers, believing they are better suited for fast food restaurants than homes and high-end restaurants.

    Rachel Carson (1907-1964) is a writer, biologist, and environmentalist. As a trained scientist and a great writer, Rachel Carson did much to shape people's attitudes toward the natural world. Born in Springdale, Pennsylvania, she shared from childhood her mother's love of books and feeling for the beauty and mystery of nature. At Pennsylvania College for Women, she first majored in English, but later learned biology. The imagination of a creative writer with a scientific lobe for fact made her books successful. After graduating with honors, she won a scholarship to Johns Hopkins University, where she earned an A.M. in zoology.

    When her father died suddenly in 1935, she took a job as an aquatic(水生的) biologist. An article for the Atlantic Monthly led to her first book, Under the Sea Wind (1941). During World War II she wrote a series of booklets on wildlife refuges(收容所). Meanwhile she had been working on a book that would make her known throughout the world. Published in 1951, The Sea Around Us became an immediate best-seller, won many honors and literary awards, and was translated into thirty-two languages. After earning enough money, she could devote full time to writing. Her next book, The Edge of the Sea (1955), was also a success.

    Rachel Carson's last book, Silent Spring (1962), became one of the most famous books of the last half of the twentieth century. Ever since the end of World War II, when the insecticide (杀虫剂) DDT came on the market, she had been worried about the dangers in the uncontrolled use of the poisons: their effect on wildlife, on human life, and on the environment. She decided to speak out. The result was a book showing how modern society has been poisoning the earth on a worldwide scale. "A few thousand words from her," wrote a newspaper editor, "and the world took a new direction."

    I was so fortunate today to be able to offer my love and help to an older lady at my local supermarket. I saw her standing there. I felt quite strange about such a situation.

    What was she looking at? As I looked, I found it was a "Shredded Pork Bun Meal Kit", which is a service that sends customers food ingredients and recipes for them to prepare their own fresh meals. "That's new," I thought. Then I watched as the lady began to dig into her handbag and tried to pull out one of the biggest magnifying glasses (放大镜) I had never seen in my whole life! "Oh, she can't read it," I realized.

    So I stood there and continued watching her. The voice in my mind often asks me to do the right thing. It told me to help her. But I argued back saying, "No. I won't offer help. It will only embarrass her and she is OK now anyway. She has the world's biggest magnifying glass to help her！"

    And I stood there longer. But the voice came back, "Help her, Nicole. Don't be embarrassed. Just do it. Offer your help." So I did it. I read and explained all the things that were included in that box. I read out the ingredients, the instructions on how to cook it and so on.

    She didn't end up buying it, but she was still quite grateful. I walked away knowing that I had helped her and made the right choice. Mostly, I had reminded her that people in this world still care about the old.

    She was seen. She was loved. And she mattered so much that a complete stranger took time to help her. And that stranger was me, a person who argued and didn't want to do so in the beginning.

    So grateful I am when I choose to listen to the voice in my heart. It is because of love. Love is all that ever really matters. I also get happiness through helping her.

    It's school time again! You're probably feeling excited and maybe a little sad for the vacation is over. Some kids feel nervous on the first day of school because of all the new things: new teachers, new friends, and maybe even a new school. Luckily, these "new" worries only stick around for a little while. Let's find out more about going back to school.

    Most teachers kick off the school year by introducing themselves and talking about what you'll be doing that year. Some teachers give students a chance to tell something about themselves to the rest of the class.

    When teachers do the talking on the first day, they often go over classroom rules so you'll know what's allowed and what's not. Pay close attention so you'll know if you need to raise your hand to ask a question and what the rules are about visiting the restroom.

    You might already know a lot of people in your class on the first day. But it's a great day to make new friends, so try to say "hello" to the kids you know and new ones that you don't. Make the first move and you'll be glad about what you did and so will your new friends!

    Most teachers let you pick your own seat on the first day, but by the second or third morning, they'll have mapped out a seating plan. It's a good idea to write down where your seat is in your notebook so you don't forget.

    Here are a few final tips for a fantastic(奇异的) first day: Get enough sleep. Have a healthy breakfast. Try your best. Develop good work habits, like writing down your assignments(作业) and handing in your homework on time. Take your time with schoolwork. If you don't understand something, ask the teacher.

    More and more people like bicycling and it is no surprise. It is fun, healthy and good for the environment.

    Maybe that's why there are 1.4 billion bicycles and only 400 million cars on roads worldwide today. Bikes can take you almost anywhere, and there is no oil cost! Get on a bicycle and ride around your neighborhood. You may discover something new all around you. Stopping and getting off a bike is easier than stopping and getting out of your car. You can bike to work and benefit(受益)from the enjoyable without polluting the environment. You don't even have to ride all the way.

    Folding(折叠) bikes work well for people who ride the train. Just fold the bike and take it with you. You can do the same on an airplane. A folding bike can be packed in a suitcase. You can also take a common bike with you when you fly. But be sure to look for information by getting on airline websites. Not all airlines are bicycle-friendly to travelers.

    Health benefits of bicycling

    It helps to prevent heart diseases

    Bicycling helps to control your weight

    A 15-minute bike ride to and from work three times a week burns off five kilos of fat in a year.

    Bicycling can improve your mood.

    Exercise like bicycling has been shown to make people feel better, more relaxed and self-confident.

For some people, walking or running outdoors is a great way to work out. What may not be so pleasant is seeing trash all over the ground. Well, some people are doing something about it. They are plogging!

"Plogging" began in Sweden. The name combines the Swedish word "plocka", which means "to pick up", and the word "jogging", which means "to run slowly". A Swedish man named Erik, started the movement in 2016. On the World Environment Day website, Erik says that he moved to Stockholm from a small community in northern Sweden. Each day he would ride his bike to work. Concerned about the amount of trash and litter he saw each day on his way to work, he took matters into his own hands. 

Plogging, by that term, may have officially begun in Sweden. But many people who exercise outdoors have been doing this for years. Take Jeff Horowitz for example. He is a personal trainer in Washington, D.C. He often picks up trash while running outside. He even has turned it into a game; he will try to pick up the trash without stopping. "I didn't know it was a thing really. This is just my personal ethics____(道德标准), where I go for a run and if I happen to see a piece of garbage lying around and it's within reach—it is a kind of a little test for me to see if I can grab it and throw it in a near trash can without stopping. And that way, I think, it gives me a little exercise and a little focus for my run. And it helps clean up the neighbourhood," he announced. 

Today, plogging is an official activity, one that is becoming increasingly popular. Cities around the world now hold plogging events. "I would just hope people would think twice before dropping garbage on the ground. We have containers on every block. So, it's easy to put your garbage in the trash cans. I just think people should think about it a little bit more. I do hope one day there will not be a need for plogging," said an interviewee.