Obama, Lady Gaga and Steve Jobs—what do they have in common? They are, of course, all Americans. And according to a survey by social networking site baidu. com, they all best illustrate(举例说明) the word “cool”.

    But just what does it mean to say someone is “cool”? Most would answer that it is something to do with being independent-minded and not following the crowd.

    Yale University art professor Robert Farris Thompson says that the term “cool” goes back to 15th century West African philosophy. “Cool” relates to ideas of grace under pressure.

    “In Africa,” he writes, “coolness is a positive quality which combines calmness, silence, and life.”

    The modern idea of “cool” developed largely in the US in the period after World War II. “Post-war 'cool' was in part an expression of war-weariness (厌战情绪), . . . it went against the strict social rules of the time,” write sociologists Dick Pountain and David Robins in Cool Rules: Anatomy of an Attitude.

    But it was the American actor James Dean who became the symbol for “cool” in the hugely successful 1955 movie Rebel without a Cause. Dean plays a tough guy who disobeys his parents and the authorities. He always gets the girl, smokes cigarettes, wears a leather jacket and beats up bullies. In the movie, Dean showed what “cool” would mean to American young people for the next 60 years.

    Today the focus of “cool” has changed to athletics (体育运动) stars. Often in movies about schools, students gain popularity on the athletics field more than in the classroom. This can be seen quite clearly in movies like Varsity Blues and John Tucker Must Die.

    But many teenagers also think being smart is cool. Chess and other thinking games have been becoming more popular in schools.

    “Call it the Harry Potterization of America—a time when being smart is the new cool,” writes journalist Joe Sunnen.

    “Body clocks” are biological methods of controlling body activities. Every living thing has one. In humans, a body clock controls normal periods of sleeping and waking. It controls the times when you are most likely to feel pain. Eating, sleeping and exercising at about the same time each day will help keep body activities normal. But changes in your life—a new job, for example—destroy the balance and thus cause health problems. You could have difficult sleeping, for example. Scientists suggest that early afternoon is the best time of day for physical exercise. They say we are stronger and faster then. Later, about four o'clock, most people feel tired because of the drop of sugar level in the blood. Early afternoon also is a good time to do tasks about memory（记忆） and mathematics. If you must study, however, do it just before going to sleep at night. Scientists say you are more likely to remember information when there is a short delay（耽搁）between study and bed. Body clocks control all the activities from day to day. They also produce changes about every ninety minutes during the day. At the end of such a time period, our ability to think hard begins to become weak. That is the time we are most likely to day-dream. Within fifteen minutes, we are ready to go back to what we were doing.

Top attractions

    Amsterdam is most famous for its artistic heritage. This tradition is proudly on display in the Rijksmuseum (translates as State Museum). Once you've taken in all that has to offer, artists, history fans, and families shouldn't pass up the chance to visit the Van Gogh Museum-containing around 700 paintings and drawings by Vincent and his contemporaries, including Gauguin, Monet, and Toulouse-Lautrec.

    Amsterdam is also home to the Anne Frank Museum, where Anne hid with her family during the Nazi occupation of the Netherlands. On a lighter note, taking a canal cruise through its extensive waterways is a rewarding way to see the Dutch capital.

    Art lovers get their kicks at:

     The Van Gogh Museum Rijksmuseum Museum het Rembrandthuis

    Food and drink

    Cheese lovers love Amsterdam. You can find an excuse to eat cheese at any time of the day here. Gouda is Holland's favorite, developing a more intense flavor the longer it's aged. Find a selection at the markets, try a cheeseboard at dinner time, or just order cubes with mustard for dipping to accompany a drink.

    When you're hungry for non-cheese food groups, you'll find Michelin-starred restaurants, vegetarian, and organic restaurants that accompany an array of global cuisine. For old-fashioned and modern Dutch food, try these Amsterdam restaurants: Moeders, Haesje Claes, Loetje, Greetje, and De Silveren Spiegel.

    Don't leave without tasting:

     Patat (hot chips with toppings) Stroopwafel (waffle cookie) Chocomel (chocolate milk)

    Amsterdam Fast Facts

    Approximate flight times:

     NYC/Newark 7 hours, 20 minutes Philadelphia 8 hours Boston 7 hours

     Miami 9 hours, 45 minutes Los Angeles 10 hours, 15 minutes

    Entry requirements: Passport must be valid for at least 3 months beyond your planned departure from the Schengen area and have 2 blank pages for entry stamp.

    If you are studying at school, do be a polite and clever student! There is no excuse for not doing your assignments. If you can't come to school, you should call your teacher or your classmate ask about homework. It is your responsibility to find out what homework you have missed. It is not the teacher's job to remind you of the missed assignments.

    You must not be absent on a test day. If you are seriously ill, call and let the teacher know you will not be there for the test. If your teacher allows a make-up test, you should take the test, again within one or two days after you return to class. Serious illness is the only reason for missing a test.

    Be on time! It is impolite to be late. Also, it bothers other students. If you must come in late, be sure to do it quietly. Have your books and papers out of your bag before you come into the classroom. Then go to your seat and sit down quietly. In the USA, it is not necessary to knock before you enter the classroom. Most teachers will give you a low grade if you are often late.

    In America, you should call your teacher by his or her last name instead of “teacher”. Also you should use Mr, Miss, Ms or Mrs before the last name (such as Mrs Smith or Mr Jones). The teacher will tell you the title that he or she likes. It is impolite in the USA to eat, drink or chew gum during class. Don't do these until the break. Also, removing your shoes in the classroom is not polite.

    Do you often dream at night? How do you feel when you dream? Is it useful to our health? “Dreams may be more important than sleep, and we all need to dream,” some scientists say.

    Dreams take up about one quarter of our sleeping time. People have several dreams each night. Dreams are like short films. They are usually in colour. Some dreams are like old films. They come to us over and over again. That may be because the dreamer is worrying about something. Dreaming may be a way of trying to find an answer. Some people get new ideas about their work from dreams. They may have been thinking about their work all day. These thoughts can carry over into dreams.

    Sometimes we wake up with a good feeling from a dream. But often we can't remember the dream. Dreams can disappear quickly from memory.

    Too much dreaming can be harmful. The more we sleep, the longer we dream. The mind is at work when we dream. That is why we may have a long sleep and still wake up tired.

    The state of Texas has not fully recovered from last year's hurricane, Harvey, as it prepares for a new season of storms. After a teleconference with President Trump and Federal Emergency Officials, Texas governor Greg Abbott said that they were taking steps on a daily basis to make sure they would be able to address any coming challenges.

    Hurricane Harvey brought record rainfall to a wide range of Texas and more rain fell over a five day period than at any time, since records have been kept in the United States beginning in the 1850s. Last year's deadly hurricanes including Harvey, Irma and Maria caused mass destruction in large parts of Texas, Louisiana, the South Atlantic states, the Caribbean and Puerto Rico. Trump praised what he called best recovery and response efforts to the disasters. They were gathering every accessible resource to ensure maximum preparation for rapid response. That's what they had last year. Disaster reaction and recovery is best achieved when it's nationally supported, state managed and locally performed.

    Abbott also mentioned that two new satellites and modem technology will help decide the path and strength of the storms. State and local governments are also planning routes, shelters, communication lines and supply chains to ensure efficient reaction to the storms. Scientists warn that, as the earth warms, storms are taking more moisture and are able to produce more rainfall. This year storms are also expected to be driven by extremely powerful winds.

    Emergency Officials say the nation has to be prepared for ever more active storms in the future. They've got to keep building the culture of preparedness in this state and in this nation. Meteorologists（气象学家）predict up to 16 storms this summer including 5 to 9 hurricanes, the most active storms will occur in the approaching Mid-August.