Most people who move to a foreign country may experience a period of time when they have a lot of stress in the new culture. This feeling is often called “culture shock” and it is important to learn how to deal with culture shock. First of all, you should know that everyone in a new situation will go through some form of culture shock. There are four general stages of cultural adjustment(适应).

    The first stage is usually referred to as the honeymoon stage. Upon arriving in a new environment, you'll be interested in the new culture. Everything will seem exciting, and everyone will seem friendly and helpful.

    The second stage is called the withdrawal stage. The excitement that you felt before changes to frustration(沮丧) as you find it difficult to deal with new problems. The language is hard to learn; friends are hard to make; simple things like shopping and going to the bank are challenges. It is at this stage that you are likely to feel anxious and homesick.

If you are one of those who manage to stick it out (坚持下来), you will enter the third stage—- the recovery stage. At this point, you'll feel more confident in the new culture. You'll start to understand and accept the way things are done and the way people behave in your new environment.

The last stage is the stability stage—- this is the point when people start to feel at home in the new culture. At this stage, you will behave well in the new culture, and prefer some aspects(方面) of the new culture to your own culture.

    There is, in a sense, a fifth stage to this process. If you decide to return home after a long period in a new culture, you may experience what is called “reverse culture shock”. This means that you may find aspects of your own culture “foreign”, because you're so used to the new culture. Reverse culture shock is usually pretty mild(温和的) and doesn't last for very long.

    If you could have one superpower, What would it be ?

    Dreaming about whether you would want to read minds , see through walls , or have superhuman strength may sound silly , but it actually gets to the heart of what really matters in your life 1

    Every day in our work , we are inspired by the people we meet doing extraordinary things to improve the world.

    They have a different kind of superpower that all of us possess : the power to make a difference in the lives of others .

    We're not saying that everyone needs to contribute their lives to the poor . Your lives are busy enough doing homework , playing sports , making friends , seeking after your dreams . But we do think that you can live a more powerful life when you devote some of your time and energy to something much larger than yourself . Find an issue you are interested in and learn more . Volunteer or , if you can , contribute a little money to a cause . Whatever you do , don't be a bystander . Get involved . You may have the opportunity to make your biggest difference when you're older . But why not start now ?

    Our own experience working together on health , development , and energy the last twenty years has been one of the most rewarding parts of our lives . It has changed who we are and continues to fuel our optimism about how much the lives of the poorest people will improve in the years ahead .

    There's a trend that more city people decide that they want to grow crops and raise some live-stock (家禽). After all, there are few things more satisfying than biting into a bunch of tender, red carrots you grow yourself, or a fresh egg from the backyard.

    Most gardeners understand that the soil in big cities is often polluted with lead and know to get their soil tested. But most are pretty clueless about how to prevent other types of pollutants, like heavy metals and asbestos(石棉)from getting into their vegetables.

    Part of the problem is that “there might be pollutants that gardeners can't test for,” says Brent Kim, a program officer. Most soil tests look for lead, cadrniunt(镉)and arsenic(砷). But they don't test things like chemicals left behind by cars, which might have escaped into the soil.

    So if you're thinking of staring an urban garden, Kim says, once you've found a plot of land, you should learn what's now an empty plot or a backyard might once have been a parking lot, a gas station or a chemical ground. “Knowing its past will give you some idea about what might be in that soil,” he says.

    “People tend to think raised beds are going to solve their pollution problem,” Kim says. But polluted soil could easily kicked onto your plants, especially if the beds are low to the ground.

    “Another consideration is that you have to be careful about the materials that you're using to build a raised bed,” Kim says. Recycling wood from an old construction site might seem like a good, eco-friendly idea. But that wood could be treated with chemicals you don't want touching your fruits and veggies, Kim says. And it's always a good idea to use gloves while gardening, and wash all your produce thoroughly.

    “I see these urban growing spaces as these oases(绿洲)in the middle of these urban environments,” Kim says. “They bring communities together, and they help people save money on fresh produce. Urban growing spaces are amazing. Let's keep doing this, but let's do it safely.”

    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.

    Since English biologist Charles Darwin published On the Origin of Species in 1859, scientists have vastly improved their knowledge of natural history. However, a lot of information is still of the speculation, and scientists can still only make educated guesses at certain things.

    One subject that they guess about is why some 400 million years ago, animals in the sea developed limbs (肢) that allowed them to move onto and live on land.

    Recently, an idea that occurred to the US paleontologist (古生物学家) Alfred Romer a century ago became a hot topic once again.

    Romer thought that tidal (潮汐的) pools might have led to fish gaining limbs. Sea animals would have been forced into these pools by strong tides. Then, they would have been made either to adapt to their new environment close to land or die. The fittest among them grew to accomplish the transition (过渡) from sea to land.

    Romer called these earliest four-footed animals “tetrapods”. Science has always thought that this was a credible theory, but only recently has there been strong enough evidence to support it.

    Hannah Byrne is an oceanographer (海洋学家) at Uppsala University in Sweden. She announced at the 2018 Ocean Sciences Meeting in Oregon, US, that by using computer software, her team had managed to link Homer's theory to places where fossil deposits (沉积物) of the earliest tetrapods were found.

    According to the magazine Science, in 2014, Steven Balbus, a scientist at the University of Oxford in the UK, calculated that 400 million years ago, when the move from land to sea was achieved, tides were stronger than they are today. This is because the planet was 10 percent closer to the moon than it is now.

    The creatures stranded in the pools would have been under the pressure of “survival of the fittest”, explained Mattias Green, an ocean scientist at the UK's University of Bangor. As he told Science, “After a few days in these pools, you become food or you run out of food... the fish that had large limbs had an advantage because they could flip (翻转) themselves back in the water.”

    As is often the case, however, there are others who find the theory less convincing. Cambridge University's paleontologist Jennifer Clark, speaking to Nature magazine, seemed unconvinced. “It's only one of many ideas for the origin of land-based tetrapods, any or all of which may have been a part of the answer,” she said.

    Let us begin by saying what causes our dreams. Our dreams do not come from another world. They are not messages from some outside source. They are not a look into the future, either.

    All our dreams have something to do with our feelings, fears, longings, wishes, needs and memories. If a person is hungry, or tired, or cold, his dreams may include a feeling of this kind. If the covers on your body, such as a quilt or a blanket, have slipped off your bed, you may dream that you are sleeping on ice or in snow. The material for the dream you will have tonight is likely to come from the experience you have today.

    So the subject of your dream usually comes from something that has effect on you while you are sleeping（feeling of cold, a noise, a discomfort, etc. ）and it may also use your past experiences and the wishes and the interests you have now. This is why children are likely to dream of fairies, older children of school examinations, hungry people of food, homesick soldiers of their families and prisoners of freedom.

    To show you how this is happening while you are asleep and how your needs and wishes can all be joined together in a dream, here is the story of the experiment. A man was asleep and the back of his hand was rubbed with a piece of absorbed cotton. He would dream he was in hospital and his charming girlfriend was visiting him, sitting on the bed and feeling his hand gently!

    There are some scientists who have made a special study of why we dream, what we dream and what those dreams mean. Their explanation of dreams, though a bit reasonable, is not accepted by everyone but it offers an interesting approach to the problem. They believe that dreams are mostly expressions of wishes that did not come true. In other words dreaming is a way of having your wishes carried out.