A business executive（主管）was deep in debt and could see no way out. He sat on the park bench, head in hands, wondering if anything could save his company.

    Suddenly an old man appeared. “I can see that something is troubling you,” he said. After listening to the executive's words, the old man said, “I believe I can help you.” He asked the man his name, wrote out a check, and pushed it into his hand saying, “Take this money. Meet me here exactly one year from today, and you can pay me back at that time.” Then he turned and disappeared as quickly as he had come.

    The executive saw a check for $ 500,000, signed by John D. Rockefeller, then one of the richest men in the world! “I can settle all my debts immediately!” he realized. But instead, the executive decided to put the uncashed check in his safe. Just knowing it was there would give him the strength to work out a way to save his business, he thought.

    With renewed optimism, he made better deals and extended terms of payment. Within a few months, he was out of debt and making money once again. Exactly one year later, he returned to the park with the uncashed check. At the agreed-upon time, the old man appeared. But just as he was about to hand back the check and share his success story, a nurse came running up and grabbed the old man.

    “I'm so glad I caught him!” she cried.” hope he hasn't been bothering you. He's always escaping from the rest home and telling people he's John D. Rockefeller.” And she led the old man away. The astonished executive just stood there.

    Suddenly, he realized that it wasn't the money, real or imagined, that had turned him around. It was his newly found self-confidence that gave him the power to achieve anything he went after.

    French writer Frantz Fanon once said: "To speak a language is to take on a world, a culture." Since the world changes every day, so does our language.

    More than 300 new words and phrases have recently made it into the Oxford Dictionary Online, and in one way or another they are all reflections of today's changing world.

    After a year that was politically unstable, it's not hard to understand the fact that people's political views are one of the main drives of our expanding vocabulary. One example is "clicktivism", a compound of "click" and "activism". It refers to "armchair activists" -- people who support a political or social cause, but only show their support from behind a computer or smart phone.

    "We had all the words around Brexit (脱欧) in the last update and we are now starting to see all the words around Trump coming into the dictionary," Angus Stevenson, Oxford Dictionaries' head of content development, told The Guardian.

    Lifestyle is also changing our language. For example, "fitspiration -- a compound of fit and inspiration -- refers to a person or thing that encourages one to exercise and stay fit and healthy. The phrase "climate refugee" -- someone who is forced to leave their home due to climate change -- reflects people's concern for the environment.

    According to Stevenson, social media was the main source for the new expressions "People feel much freer to coin their own words these days." he said.

    But still, not all newly- invented words get the chance to make their way into a mainstream dictionary. If you want to create your own hit words, Angus Stevenson suggests that you should not only make sure that they are expressive and meaningful, but also have an attractive sound so that people will enjoy saying them out loud.

    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.

    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.

    Language is always changing. In a society where life continues year after year with few changes, the language does not change either. The earliest known languages had difficult grammar but a small, limited vocabulary. Over the century, the grammar changed, and the vocabulary grew. For example, the English and Spanish people who came to America during the sixteenth century gave names to all the new plants and animals they found. In this way, hundreds of new words were introduced into English and Spanish vocabularies. Today life is changing very fast, and language is changing fast too.

     There are several major(主要) language families in the world. Some scientists say there are nine main families, but other scientists divide them differently. The languages in each family are connected, and scientists think that they came from the same parent language. About 3 percent of the people in the world speak languages that are not in these major families.

    This year's flu season is pretty scary. To try to minimize the effects, public officials are still urging anyone who hasn't yet gotten their flu shot to get one as soon as possible. However, even if every single person got a shot in the arm, the vaccine(疫 苗)—with its excellent 36 percent effectiveness—would not prevent everyone from getting infected with the annoying virus. Knowledge is power, so here's what goes on in your body when you come down with the flu.

    The influenza virus primarily attacks your nose, throat, and the tubes that lead to your lungs. But the flu is so much more than that. Your muscles ache, your head hurts, and your appetite goes down, among other things. To our surprise, almost all of these symptoms have less to do with the virus itself than with your immune(免疫的)response to them. Unfortunately, the very defense you have in place to get rid of the flu is the reason you feel so painful when you recover.

    The virus usually enters through your mouth, typically by way of your hands. But it takes a few days for symptoms to set in. While this process might cause some harm to your nose and throat, it's nothing major, and nothing like the symptoms that typically accompany a bad or even mild case of the flu.

    The real fun starts when your immune system begins to fight. Your immune system comes in two parts: the innate system and the adaptive. The innate immune system is essentially an all-purpose tool. As soon as your body senses the presence of any injury or invader, the innate immune system launches into action by producing tiny proteins called cytokines and chemokines. The cytokines reproduce almost immediately and start to attack the virus. This increase in immune cells creates a serious inflammation(炎症) throughout the body. But the worst is still to come.

    Meanwhile, the chemokines work with the adaptive immune system to help create T cells. These cells are a special type of white blood cell that works in a much more specific way: They find the influenza virus, identify what's special about it, and create something unique on their surface that finds and destroys similar invaders.

    A few weeks ago, I called an Uber to take me to the Boston airport for a flight home for the holidays. As I slid into the back seat of the car, the warm intonations(语调) of the driver's accent washed over me in a familiar way.

    I learned that he was a recent West African immigrant with a few young children, working hard to provide for his family. I could relate: I am the daughter of two Ethiopian immigrants who made their share of sacrifices to ensure my success. I told him I was on a college break and headed home to visit my parents. That's how he found out I go to Harvard. An approving eye glinted at me in the rearview window, and quickly, we crossed the boundaries of rider and driver. I became his daughter, all grown up — the product of his sacrifice.

    And then came the fateful question: "What do you study?" I answered "history and literature" and the pride in his voice faded, as I knew it might. I didn't even get to add "and African-American studies" before he cut in, his voice thick with disappointment, "All that work to get into Harvard, and you study history?"

    Here I was, his daughter, squandering the biggest opportunity of her life. He went on to deliver the age-old lecture that all immigrant kids know. We are to become doctors (or lawyers, if our parents are being generous) — to make money and send money back home. The unspoken demand, made across generations, which my Uber driver laid out plainly, is simple: Fulfill your role in the narrative(故事) of upward mobility so your children can do the same.

    I used to feel anxious and backed into a corner by the questioning, but now as a junior in college, I'm grateful for their support more than anything. This holiday season, I've promised myself I won't huff and get annoyed at their inquiries. I won't defensively respond with "but I plan to go to law school!" when I get unrequested advice. I'll just smile and nod, and enjoy the warmth of the occasion.