Deborah Cohen is a senior natural scientist at the Rand Corp and the author of the book A Big Fat Crisis: The Hidden Forces Behind the Obesity Epidemic and How We Can End It. According to the book, there are lots of misunderstandings of obesity.

1).If you're obese, blame your genes.

    Obesity rates have increased. Yet, between 1980 and 2000, the number of Americans who are obese has doubled—too quickly for genetic factors to be responsible.

    At restaurants, a dollar puts more calories on our plates than ever before, because restaurant meals usually have more calories than what we prepare at home, so people who eat out more frequently have higher rates of obesity than those who eat out less.

2).If you're obese, you lack self-control.

    Research shows that if we are faced with too much information, we have a tendency to make poor dietary choices. Our world has become so rich in temptation that we can be led to consume too much in ways we can't understand. Even the most vigilant (警觉的) people may not be up to the task of controlling themselves.

3).Lack of access to fresh fruits and vegetables is responsible for obesity.

    Although the US Department of Agriculture estimates that fewer than 5 percent of Americans live in the “food deserts”, about 65 percent of the nation's population is overweight or obese. For most of us, obesity is not related to access to more fresh fruits and vegetables, but to the choices we make in supermarkets.

4).The problem is not that we eat too much, but that we don't exercise.

    Michelle Obama's “Let's Move” campaign is based on the idea that if kids exercise more, childhood obesity rates will decrease. But there was no significant decrease in physical activity levels as obesity rates climbed in the 1980s and 1990s. In fact, although a drop in work-related physical activity may account for up to 100 fewer calories burned, leisure physical activity appears to have increased. The problem is that we eat too much.

    Billionaire Bill Gates has offered the many thousands of graduates some career and life advice. Over a series of 14 tweets in his Tweeter posted last Monday, the world's richest man used the words “impact”, “happiness” and “progress”. He did not mention money. Instead, he told the graduates what jobs he would be looking for if he started out today.

“AI (artificial intelligence), energy and bio-sciences are promising fields where you can make a huge influence”, he wrote. Earlier this year, Gates—who famously dropped out of Harvard to found Microsoft—said that artificial intelligence had “ phenomenal” potential, and “anything connected with that would be an exciting lifetime career.” In the same speech at Columbia University, he said there is a huge growing demand in the energy field to develop reliable, cheap and clean energy.

    As well as urging new graduates to surround themselves with people who challenge you, teach you, and push you to be your best self, Gates reminded them to think of others, especially the less fortunate.

    He wrote that it had taken him decades to learn about the world's worst unfairness and described this lack of early understanding as his one big regret. “You know more than I did when I was your age,” he wrote, “ You can start fighting unfairness, whether down the street or around the world sooner.”

    He finished by asking graduates to consider the progress human has already made, saying that he believe the world is getting better. “ That matters because if you think the world is getting better, you want to spread the progress to more people and places.”

    When it comes to generation gap (代沟), we usually think of different tastes in music, or pastimes. But now the generation gap is handwriting. After one teacher in Tennessee discovered that she had students who couldn't read what she was writing on the board, she posted it on the Internet saying that handwriting should be taught in schools.

    Others who are against it claim that handwriting has become out of time in our modern world. Typed words have become a main form of communication. Once a practical skill, handwriting is no longer used by most of Americans. It is no longer taught in schools, and some claim that the time that it would take to teach it could be put to better use, for example, by teaching the technical skills.

    But even in today's world there are still plenty of reasons to pick up a pen and write on the paper. In America, signatures (签字) by hand are still often required, for example, signing for a registered letter and buying a house. And original signatures are much more difficult to fake (伪造).

    There is also strong evidence that writing by hand is good for the mind. It makes a different part of the brain active and improves fine moving skills in young children. People are also more likely to remember what they write by hand than what they type, and the process of writing by hand has been shown to stimulate ideas. Not only those, studies have shown that kids who write by hand learn to read and spell earlier than those who don't.

    Yes, we live in a modern world, but we live in a modern world of basic and important values.

    The students are having their chemistry class. Miss Li is telling the children what water is like. After that, she asks her students some questions, “Boys and girls! What is water? Can you tell me?" She waits for a few minutes, but no one answers her. Then Miss Li asks again. “Why don't you answer my question? I tell you what water is like, right?”

    Then a boy puts up his hand and says, “Miss Li, you tell us that water has no color and no smell. But I think that water is something that is black when I wash my hand in it.” All the students begin to laugh. Miss Li laughs too. Then another boy puts up his hand, Miss Li says “What do you think, Wang Bing?” The boy says:” Miss Li, where can we find water that has no color and no smell?”

    “Why do you say so?” Miss Li asks.

    “The water in the river behind my house is always black and it has a bad smell.” answers the boy. And most of the children think he is right.

 “I am sorry to hear that, children.” says the teacher. “Our water is getting dirtier. That is a problem. All of us must try our best to make it clean again.”

    World-famous scientist Stephen Hawking has died at the age of 76. He was often called the most brilliant theoretical physicist since Albert Einstein. But his amazing career actually started as a young man who struggled to get around to doing his homework at Oxford University where he studied physics. He then went on to Cambridge to research cosmology, the study of the origin of universe.

    When he was 21, Hawking's life hit a big hurdle. He was diagnosed with Motor Neurone Disease. The disease causes the brain to stop sending messages to a person's muscles. At the time, doctors said he would only live for around 2 years, but he proved them very, very wrong.

    And with the help of a special wheelchair and speech computer, Hawking spent much of his time researching the beginning of the universe and black holes. His most famous discovery was probably when he demonstrated that black holes emit some radiation, which has since become known as Hawking Radiation. He also spent a lot of time thinking about what existed before the big bang.

    Hawking wrote books that explained his big ideas in ways that could be understood by the average person. In 1988 he published A Brief History of Time. It became really popular and sold more than 10 million copies. However, he wasn't just known for his books. He also had a lot of fun becoming a regular on TV screens around the world. He even had a big Hollywood film made about his life.

    Throughout his life Stephen Hawking inspired people to look beyond our planet and expand our knowledge of the universe. His family says that he'll be greatly missed and the legacy of his amazing ideas will live on.

    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.