Our body clock, or natural body rhythm, influences our energy and alertness. Paying attention to it can help us choose the suitable time of the day when we best perform specific tasks.

    The reality, however, is that most of us organize the time around work demands, school deadlines, commuting or social events. Doing whatever the body feels like doing is a luxury in today's fast-paced modern society.

    But that doesn't mean it isn't worth trying. Obeying our body clock has significant health benefits. Disrupting our natural body rhythm, on the other hand, has been linked to problems such as depression, obesity, or headache, says Steve Key, a biology professor.

    When the body clock can synchronize (使…同步) the rhythms of its natural processes, it “gives us an advantage in daily life”, says Key.

    According to him, when it comes to cognitive (认知的) work, most adults perform best in the late morning. As our body temperature starts to rise just before awakening in the morning and continues to increase until midday, our memory, alertness and concentration gradually improve.

    However, he adds, our ability to concentrate typically starts to decrease soon thereafter. Most of us are more easily distracted (分心) between noon and 4 pm.

    Alertness also tends to fall after eating a meal and sleepiness tends to peak around 2 pm, making that a good time for a nap.

    Surprisingly, tiredness may increase our creative powers. For most adults, problems that require open-ended thinking are often best dealt with in the evening when they are tired, according to a study in the journal Thinking & Reasoning.

    When choosing a time of the day to exercise, paying attention to your body clock can improve results. Physical performance is usually best from about 3 to 6 pm, says Michael Smolensky, a professor of biomedical engineering.

    Of course, not everyone's body clock is the same, making it even harder to synchronize natural rhythms with daily plans.

You might think people all over the United States have Wi-Fi—wireless Internet service—and mobile phones. But there is no such service in Green Bank, West Virginia, a tiny town four hours from the U.S. capital, Washington D.C. Fewer than 150 people live in Green Bank, which has two churches, an elementary school and a public library. It is also home to the largest radio telescope in the world.

    There is a ban on Wi-Fi in Green Bank, along with anything else that can create electromagnetic(电磁的)waves. Officials say the waves could disturb the signals the telescope receives.

For many Americans, a visit to Green Bank is a little like returning to the 1950s. To get there, you must read road signs—because there is no GPS service in the town. People can connect with the Internet through telephones, but wireless service is not allowed.

    The observatory(天文台)is one of the largest employers in the area. The federal National Science Foundation(NSF) spends about ＄8.2 million a year to operate the observatory, telescope and educational center.

    Jonah Bauserman is a technician. If he supposes there is signal that is not allowed in the zone, he drives to the house where the signal is coming from and checks it. But once a week, when the device is cleaned, some banned devices are allowed near it.

    People in the town respect the work of the scientists. And they say they are happy to live without Wi-Fi and mobile phones. "You know, instead of sitting here on our phones and other devices we're out fishing and hunting and going to each other's houses." Everyone knows each other and communication is almost always face-to-face.

    Crossing your legs is an extremely common habit. While you may find it comfortable to sit with one knee crossed over the other, it might be causing health problems that you are not aware of.

    A study published in Blood Pressure Monitoring stated that sitting with your legs crossed can increase your blood pressure. The reason this happens is because the blood in your legs has to work against gravity to be pumped back to your heart, crossing one leg over the other increases resistance, making it even harder for the blood to circulate. You won't feel any immediate effects, but sitting for long periods of time will hurt you forever.

    Crossing your legs can also lead to neck and back pain. Ideally, it's best for our bodies to sit with our feet planted flat, hip width apart, on the floor, but it's not easy to maintain perfect posture all day at the office. When you sit with your legs crossed your hips are in a twisted position, which can cause one of your pelvic bones(骨盆) to rotate. Since your pelvic bone supports your neck and spine（脊椎）, this can cause pressure on your lower and middle back and neck.

    You also might notice that when you sit with your legs crossed for long periods of time your feet and legs get painful or have the feeling of being asleep. This is because when one leg sits on top of the other it causes pressure on the veins（静脉） and nerves in your legs and feet. It can cause numbness and/or temporary paralysis in the legs, ankles, or feet. While the feeling of discomfort may only last a minute or two, repeatedly crossing your legs until they feel numb can cause permanent nerve damage.

    So next time you sit down, try to get yourself in the habit of sitting with both of your feet on the floor. Not only will it help your posture and stability, but it will also save your health in the long run.

    On April 8th, 2013, the world felt sorry because of the death of former British Prime Minister, Margaret Thatcher, who died at the age of 87. Besides being the country's longest leader (1979-1990) in the 20th century, she was the first woman to lead Britain. She worked hard and did well in her work, so she was called" Iron Lady".

    Whatever you think of Margaret Thatcher, the thing everyone does agree on is that she was a woman with great decisions. When she took over Britain in 1979, she led a country that was in economic trouble. She faced a lot of problems because of the poor economic position.

    In order to make the country become strong again, Ms. Thatcher had to make some hard and special decisions like raising interest rates and even taxes at a time when most British people were living a hard life. In this way she led Britain to run out of economic troubles.

    Early in her second term, just as things were looking a little better, she faced another problem — a strike by the British Miners Union. Once again, the Iron Lady stood her ground to stop the longest strike in the country's history.

    In 1982, Argentina said that they had owned the Falkland Islands since the 19th century. Britain, however, considered the islands to be one of their overseas dependent territories (领土). Margaret Thatcher tried to talk about the problem with Argentines. But Argentines didn't agree with her ideas, so Ms. Thatcher did what any strong leader would do — send in the British Army. It took 74 days, and on 14th June 1982, the Argentine army finally failed and Britain controlled the Falkland Islands again.

    When Ms. Thatcher resigned in 1990, she left behind a country that was very strong. Unluckily, during the last few years of her life, something was wrong with her mind. She hardly remembered anything that was happening around her and even what she had done during her wonderful lifetime.

    The deadliest Ebola(埃博拉病毒) outbreak in recorded history is happening right now. The outbreak is unprecedented(空前的) both in the number of people who have gotten sick and in the geographic scope. And so far it's been a long battle that doesn't appear to be slowing down.

    Ebola is both rare and very deadly. Since the first outbreak in 1976, Ebola viruses have infected thousands of people and killed roughly 60 percent of them. Symptoms can come on quickly and kill fast.

    The current outbreak started in Guinea sometime in late 2013 or early 2014. It has since spread to Sierra Leone and Liberia, including some capital cities. And one infected patient traveled on a plane to Nigeria, where he spread the disease to several others and then died. Cases have also popped up in various other countries throughout the world, including in Dallas and New York City in the United States.

    The Ebola virus has now hit many countries, including Guinea, Liberia, Sierra Leone, Nigeria, Senegal, and the United States. The virus, which starts off with flu-like symptoms and sometimes ends with bleeding, has infected about 6,500 people and killed more than 3,000 since this winter, according to the World Health Organization on September 30, 2014.

    There are some social and political factors contributing to the current disaster. Because this is the first major Ebola outbreak in West Africa, many of the region's health workers didn't have experience or training in how to protect themselves or care for patients with this disease.

    Journalist David Quammen put it well in a recent New York Times article, "Ebola is more dangerous to humans than perhaps any known virus on Earth, except rabies(狂犬病) and HIV. And it does its damage much faster than either."

Hopefully, researchers are working to find drugs, including a recent $50 million push at the National Institutes of Health. And scientists are working on vaccines(疫苗), including looking into ones that might be able to help wild chimpanzees, which are also susceptible to the disease. The first human Ebola vaccine trial is scheduled to start in the spring of 2015.

    Need a fall fix? Try one from these great places.

    ⒈Mackinac Island, Michigan

    The only way to reach this famed car-free island is by boat and ferry, and once visitors arrive, they are attracted by the history, scenery and fall colors. "It's a throwback to years past, a little town, and there's a big state park as well," Blackwell says. "You're allowed to have boats all around the island."

    ⒉Tellico Lake, Tennessee

    With nearly 400 miles of shoreline, this waterway flowing out of the Great Smoky Mountains is largely unexploited, well-protected in its natural state. Fall visitors find a range of colors reflecting in the clean waters, says Blackwell, who vacationed in the area with his family as a child. "The thick forest there just allows you to see more greenery and wildlife."

    ⒊Dillon Reservoir, Colorado

    With an hour from Denver, this lake is home to what claims to be the nation's highest sailing club, at an altitude of more than 9,000 feet. Marinas in the towns of Dillon and Frisco make it easy to get out on the water and to see the bright yellows and golds of fall leaves. "People are surprised that there's boating in Colorado, and you can see the mountains just before the snowball," Blackwell says.

    ⒋Lake Monroe, Indiana

    The state's largest lake is surrounded by more than 13,000 acres of protected forest and three recreation areas, making it an ideal place to see fall colors, particularly from oaks and the tulip poplar, the state tree. " It's a gem (宝石) in southern Indiana," says Blackwell, who grew up in the area. "There are lots of different activities: canoeing, kayaking and fishing."