“One thing I enjoy about my job is that I can work on something that is actually active,” says Game McGimsey, an American volcanologist (火山学家). Part of his job includes keeping an eye on Alaska's many active volcanoes and giving people a heads-up when a volcano might erupt (喷发).

    Like most jobs in the sciences, volcanology requires a lot of education. McGimsey received an undergraduate degree in geology at the University of North Carolina, then landed an internship (实习期) with a geologist at the USGS (美国地质勘探局) whose area of expertise was volcanoes. After earning a graduate degree at the University of Colorado, McGimsey accepted a job with the USGS and has been with the Alaska Volcano Observatory for 25 years.

    Volcanoes can influence the world in ways we might not think about. For example, on Dec. 15, 1989, a 747 jetliner (a large airplane) flew through a thick ash (灰) cloud produced by Mount Redoubt, an Alaskan volcano that hadn't erupted in 25 years. The ash caused all four engines to die, and the plane's electronics went dead.

    “The plane was within several thousand feet of flying into the mountains below when the pilots got a couple of the engines restarted and landed safely in Anchorage,” McGimsey says. It cost nearly $80 million to repair the damage to the plane.

    Such situations show just how dangerous volcanoes can be. However, volcanologists know the risks and are prepared to protect themselves.

    “There is certainly a higher danger level in volcanology than some other jobs,” McGimsey admits. “We understand how serious the danger is, and we don't like taking unnecessary chances. We avoid getting too close to an erupting volcano, because it's not worth injury or death simply to get a rock or a photograph.”

                                            Robot Surgeon (外科医生) Succeeds without Help from Human Doctors

         Humans make mistakes. Even surgeons with years of experience are not infallible. But what if these doctors could pool their knowledge and experience together and create a surgical standard of care, to be carried out by machines?

    That's the idea behind surgical robots, which may soon perform most surgeries, from sewing up tiny wounds to performing heart procedures. Many of these operations are, in fact, already completed with the assistance of robots. But a recent test suggests that robots in the operating room may soon go a step further, performing on soft tissue completely on their own, from start to finish.

    The Smart Tissue Autonomous Robot (STAR), successfully completed surgeries on pigs. “We're the first group to develop autonomous robotic surgery with soft-tissue surgery, and when compared to standard operation, it's better, ”says Peter Kim, professor of surgery. “The idea is not to replace surgeons; it will make the surgeons better and make the procedures safer.”

    A recent Mayo Clinic study found that major surgical errors-including operating on the wrong site or side of the body, or even leaving tools or objects inside the patient-occur every one out of 22, 000procedures. That's rare, but robots like STAR would aim to lower the number even further.

    In the da Vinci surgical system, surgeons place their arms inside instruments and use their hands to control the movement of robotic tools on the operating table from afar. The robot's every major move is controlled by surgeons, and thus its results may vary based on the surgeon's training or experience.

    STAR, on the other hand, is entirely autonomous. It's not only able to work on its own and perform surgeries with a more flexible “hand”, but it's able to react to the unexpected incidents. Cutting into hard tissue like bones is one thing, but operating on moving soft tissue is far more complex. STAR reacts to a changing environment, similar to how self-driving cars are programmed to not only drive on the highway, but also react to another driver making a mistake and getting in your way.

    It was my first day back home since starting college. A lot had changed in the last year. Not with my hometown but with me. I had left as a 17-year-old boy and had now returned as an 18-year-old man. In the city, I was living on my own, had a part-time job and was studying. Even the government recognized I was an adult: I had a driver's license. So here I was, on my summer vacation, walking down the main street with my father, desperate for him to acknowledge how mature I was. When his recognition failed to appear, I took matters into my own hands. “Dad,” I said casually, “I'm thirsty. Let's go for a beer.” It was the first time I'd ever mentioned beer in front of my father, let alone ask him to drink one with me.

    He turned to me with a curious expression on his face. “A beer? Well, 1 guess you're old enough now. Let's go to Sailors' Bar. It's where my cousin Tom, your uncle, used to drink. You remember him, right?”

    I had only some vague recollection of my uncle. He was the black sheep of the family. We didn't talk about him much. What ever happened to Uncle Tom, Dad? I haven't seen him in years,” I said as we continued towards the bar.

     “Neither have I, unfortunately. He was a good kid once. But things changed,” my father said mournfully. As a boy, he explained, there had been no better-behaved boy than Tom. But after leaving school, he moved to the city and fell in with bad company. He started going out every night, drinking in nightclubs and playing cards. Soon he lost everything and had to beg his mum to pay his debts. She agreed on condition that he returned home.

    My dad took a deep breath and continued his tale. "Things settled down for a while. He married a lovely woman, gave up his bad habits. But it didn't last. He was soon back to his old ways. He couldn't resist. He was at Sailors, Bar almost every night. His poor mother died of grief and shame. His wife followed her soon after.

     “What ruined him was alcohol He told me once, when a man begins drinking, he never knows where it'll end. ‘So', Tom warned me. ‘be cautious about your first drink!'

     “He went from bad to worse. Last year Tom sent me a letter saying he had been found guilty of stealing, and sent to prison for ten years.”

    Dad finished talking just as we reached the front door of Sailors' Bar. “Anyway, here we are. Let's go in,” he said. But understood. I put my arm around my father and said, “I'm not thirsty anymore, Dad. Let's go home.”

    Washington, D.C. Bicycle Tours

    Cherry Blossom Bike Tour in Washington, D.C.

    Duration: 3 hours

    This small group bike tour is a fantastic way to see a world-famous cherry trees with beautiful flowers of Washington, D.C. Your guide will provide a history lesson about the trees and the famous monuments where they blossom. Reserve your spot before availability — the cherry blossoms—disappear!

    Washington Capital Monuments Bicycle Tour

    Duration:3 hours (4 miles)

    Join a guided bike tour and view some of the most popular monuments in Washington, D.C. Explore the monuments and memorials on the National Mall as your guide shares unique facts and history at each stop. Guided tour includes bike, helmet, cookies and bottled water.

Capital City Bike Tour In Washington, D.C.

    Duration:3 hours

    Morning or Afternoon, this bike tour is the perfect tour for D. C. newcomers and locals looking to experience Washington, D.C. in a healthy way with minimum effort. Knowledgeable guides will entertain you with the most, interesting stories about Presidents, Congress, memorials, and parks. Comfortable bikes and a smooth tour route(路线）make cycling between the sites fun and relaxing.

Washington Capital Sites at Night Bicycle Tour

    Duration:3 hours (7 miles)

    Join a small group bike tour for an evening of exploration in the heart of Washington, D.C. Get up close to the monuments and memorials as your bike the sites of Capitol Hill and the National Mall. Frequent stops are made for photo taking as your guide offers unique facts and history. Tour includes bike, helmet, and bottled water. All riders are equipped with reflective vests and safety lights.

Larry was on another of his underwater expeditions(探险)but this time, it was different. He decided to take his daughter along with him. She was only ten years old. This would be her first trip with her father on what he had always been famous for.

    Larry first began diving when he was his daughter's age. Similarly, his father had taken him along on one of his expeditions. Since then, he had never looked back. Larry started out by renting diving suits from the small diving shop just along the shore. He had hated them. They were either too big or too small. Then, there was the instructor. He gave him a short lesson before allowing him into the water with his father. He had made an exception. Larry would never have been able to go down without at least five hours of theory and another similar number of hours on practical lessons with a guide. Children his age were not even allowed to dive.

After the first expedition, Larry's later diving adventures only got better and better. There was never a dull moment. In his black and blue suit and with an oxygen tank fastened on his back, Larry dived from boats into the middle of the ocean. Dangerous areas did not prevent him from continuing his search. Sometimes, he was limited to come to a cage underwater but that did not bother him. At least, he was still able to take photographs of the underwater creatures.

    Larry's first expedition without his father was in the Cayman Islands. There were numerous diving spots in the area and Larry was determined to visit all of them .Fortunately for him, a man offered to take him around the different spots for free. Larry didn't even know what the time was, how many spots he dived into or how many photographs he had taken. The diving spots afforded such a wide array of fish and sea creatures that Larry saw more than thirty varieties of creatures.

Larry looked at his daughter. She looked as excited as he had been when he was her age. He hoped she would be able to continue the family tradition. Already, she looked like she was much braver than had been then. This was the key to a successful underwater expedition.

    Are you interested in travelling? Here are famous national parks where travellers mostly like to go in America.

    ⒈Great Smoky Mountains National Park

    Visitors: 11,388,893

    The name "Great Smoky Mountains" comes from the fog over this mountain range situated along the North Carolina-Tennessee border. Established in 1934, it is not just home to a diverse ecosystem of plants and animals, but also home to rich Appalachian cultures. Visitors there can see over 100 waterfalls, go boating on Fontana Lake and hike the Appalachian Trail. It's also an excellent vantage point to see the leaves change in the fall.

    ⒉Grand Canyon National Park

    Visitors: 6,254,238

    The Grand Canyon is the result of over 70 million years of geological events creating the Colorado Plateau, glaciers and valleys, while the Colorado River carved its way through the valleys. It is truly a natural splendor!

    When President Roosevelt first visited it in 1903, he said, "The Grand Canyon fills me with awe. It is beyond comparison – beyond description."16 years later, it was signed by President Woodrow Wilson, officially viewing the Grand Canyon a national park.

    ⒊Yosemite National Park

    Visitors: 4,336,890

    In addition to being a national park, Yosemite is designated as a World Heritage Site. Yosemite National Park is in Central California in the western Sierra Nevada. Though it covers around 1,168 square miles of area, visitors spend most of their time in the 5.9 square-mile area of the Yosemite Valley where there are some most famous sites like Yosemite Falls, and Cook's Meadow Loop.

    ⒋Zion National Park

    Visitors: 4,504,812

    Settled in Southwestern Utah is Zion National Park. It has some of the most unique landscapes packed with mountains, valleys, rivers, desert and forests.

    Zion National Park is also an important place to study ancient humans who made the area their home about 8,000 years ago. Some of the park's most notable attractions include Angel's Landing, Kolob Arch, the Narrows, etc.