Have you heard of the following people? Maybe yes, maybe no. But they may be an inspiration for you.

    The Tree Lady

    Kate Sessions was an American botanist and landscape architect closely associated with San Diego, California. After becoming the first woman to graduate from the University of California, Berkeley, she took a job as a teacher far south in the dry desert town of San Diego. Kate decided that San Diego needed trees more than anything else. Therefore, this young woman single-handedly started a movement transforming the town into the leafy, garden-filled place as it is today.

    The Snowflake(雪花) Man

    Wilson Bentley is one of the first known photographers of snowflakes. His enthusiasm for taking photos began from his boyhood and was often misunderstood in his time, but his determination revealed two important truths: no two snowflakes are alike; and each is surprisingly beautiful. In 1931, he worked with William J. Humphreys of the U.S. Weather Bureau to publish Snow Crystals, a book containing 2500 photographs.

    The Father of His Country

    By the late 1760s, George Washington had experienced firsthand the effects of rising taxes imposed (征收) on American colonists by the British, and came to believe that it was in the best interests of the colonists to declare independence from England. During the American War of Independence, he led the colonial forces to victory. In 1878, he was elected president of the Convention that wrote the U.S. Constitution. Two years later, Washington became American's first president. His retirement from office after two terms established a tradition that lasted until 1940, when Franklin Delano Roosevelt won a third term. The 22^nd Amendment (1951) now limits the president to two elected terms.

    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.

    If plastic had been invented when the Pilgrims sailed from Plymouth, England, to North America-and their Mayflower had been stocked with bottled water and plastic- wrapped snacks, their plastic waste would likely still be around four centuries later. Atlantic waves and sunlight would have worn all that plastic into tiny bits. And those bits might still be floating around the world's oceans today, waiting to be eaten by some fish or oyster, and finally perhaps by one of us.

    Because plastic wasn't invented until the late 19th century, and its production only really took off around 1950, we have a mere 9.2 billion tons of the stuff to deal with. Of that, more than 6.9 billion tons have become waste. And of that waste, a surprising 6.3 billion tons never made it to a recycling bin-the figure that shocked the scientists who published the numbers in 2017.

    No one knows how much unrecycled plastic waste ends up in the ocean, the earth's last sink. In 2015, Jenna Jam beck a University of Georgia engineering professor, caught everyone's attention with a rough estimate between 5.3 million and 14 million tons of plastic waste each year just come from coastal regions.

    Meanwhile, ocean plastic is estimated to kill millions of marine(海洋的）animals every year. Nearly 700 species, including endangered ones, are known to have been affected by it. Some are harmed visibly, stuck by abandoned things made of plastic. Many more are probably harmed invisibly. Marine species of all sizes, from zooplankton to whales, now eat microplas-tics, the bits smaller than one-fifth of an inch across.

    "This isn't a problem where we don't know what the solution is, "says Ted Siegler, a Vermont resource economist who has spent more than 25 years working with developing nations on garbage." We know how to pick up garbage. Anyone can do it. We know how to deal with it. We know how to recycle. "It's a matter of building the necessary institutions and systems, he says, ideally before the ocean turns into a thin soup of plastic.

The Greatest show on Earth

    The Olympic Games are the greatest festival of sports in the world. Every four years, many countries send their best sportsmen to compete for the highest honour in sport. As many as 6, 000 people take part in over 20 sports. For the winners, there are gold medals and glory. But there is honour, too, for all who compete, win or lose. That is in the spirit of the Olympics—to take part is what matters.

    The Olympic Games always start in a bright colour and action. The teams of all the nations parade in the opening ceremony and march round the track. The custom is for the Greek team to march in first, for it was in Greece that the Olympics began. The team of the country where the Games are being held—the host country—marches in last.

    The runner with the Olympic torch (火炬) then enters the stadium and lights the flame. A sportsman from the host country takes the Olympic oath (宣誓) on behalf of all the competitors. The judges and officials also take an oath. After the sportsmen march out of the stadium, the host country puts on a wonderful display.

    The competitions begin the next day. There are usually more than twenty sports in the Games. The rule is that there must be at least fifteen. The main events are in track and field, but there are a few days before these sports start. Each day the competitors take part in different sports, like riding, shooting, swimming, and cross-country running. Points are gained for each event. Medals are awarded for the individual winners and for national teams.

    More and more women are taking part in the Games. They first competed in 1900, in tennis and golf. Women's swimming events were introduced in 1912. But it was not until 1928 that there were any track and field events for women. Now they compete in all but half a dozen of the sports. In horse riding, shooting, and boat racing, they may compete in the same events as men.

Washington, D.C. Bicycle Tours

Cherry Blossom Bike Tour in Washington, D.C.

    Duration Tour

    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(7miles)

    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 you 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.

Do you know of anyone who uses the truth to deceive? When someone tells you something that is true, but leaves out important information that should be included, he can give you a false picture.

For example, some might say, "I just won a hundred dollars on the lottery. It was great. I took that dollar ticket back to the store and turned it in for one hundred dollars!"

This guy's a winner, right? Maybe, maybe not. In fact, he bought $200 worth of tickets. He's really a big loser!

He didn't say anything that was false, but he left out important information on purpose. That's called a half-truth. Half-truths are not technically lies, but they are just dishonest.

Some politicians often use this trick. During Governor Smith's last term, her state lost one million jobs and gained three million jobs. Then she seeks another term. One of her opponents says, "During Governor Smith's term, the state lost one million jobs!" That's true. However, an honest statement would have been, "During Governor Smith's term, the state had a net gain of two million jobs."

Advertisers will sometimes use half-truths. It's against the law to make false statements sol they try to mislead you with the truth. An advertisement might say, "Nine out of ten doctors advised their patients to take Yucky Pills to cure toothache." It fails to mention that they only asked ten doctors and nine of them work for the Yucky Company.

This kind of deception happens too often. It's a sad fact of life: Lies are lies, and sometimes the truth can lie as well.