In 1905, as part of his Special Theory of Relativity, Albert Einstein published the point that a large amount of energy could be released from a small amount of matter. This was expressed by equation E = me 2(energy = mass times the speed of light squared). But bombs were not what Einstein had in mind when he published this equation.

    In 1929, he publicly declared that if a war broke out he would “refused to do war service, direct or indirect…” His position would change in 1933, as the result of Adolf Hitler's coming into power in Germany.

    Einstein's greatest role in the invention of the atomic bomb was signing a letter to President Franklin Roosevelt urging that the bomb be built because some physicists feared that Germany might be working on an atomic bomb. Among those concerned were physicists Leo Szilard and Eugene Wigner. But Szilard and Wigner had no influence with those in power. So in July 1939 they explained the problem to someone who did: Albert Einstein. After talking with Einstein, in August 1939 Szilard wrote a letter to President Roosevelt with Einstein's signature on it, which was delivered to Roosevelt in October 1939.

    Germany has invaded Poland the previous month; the time was ripe for action. That October research of a-bomb began but proceeded slowly because the invention of the atomic bomb seemed distant and unlikely. In April 1940 an Einstein letter, ghost-written by Szilard, pressed the researchers on the need for “greater speed”.

    As the realization of nuclear weapons grew near, Einstein looked beyond the current war to future problems that such weapons could bring. He wrote to his friend about his fear about the future use of the a-bomb.

    The atomic bombings of Japan occurred three months after Germany gave in.

In November 1954, five months before his death, Einstein summarized his feelings about his role in the creation of the atomic bomb: “I made one great mistake in my life… when I signed a letter to President Roosevelt recommending that atom bombs be made; but there was some justification— the danger that the Germans would make them”.

    Traffic problems are an everyday concern in many cities，including Washington，DC．A growing number of Washingtonians are turning to bicycles to get to and from work．In fact，the number of commuters who use bicycles has doubled in the city since 2007．

    Ralph Buehler teaches urban planning at the Virginia Polytechnic Institute and State University，popularly known as Virginia Tech．He has written a book about urban biking，calledCity Cyclin . g．He says there is a reason why urban bike tiding is now becoming more popular．

    “Over the last 60 to 70 years，cities in America have adapted to the automobile．”

    “Most cities took advantage of the money coming for the interstate highway system，from the federal government，  starting in 1956．There was a 90 percent federal match(补贴)so the cities only had to put up 10％．It was very tempting．”

    In the years after World War Two，many Americans moved to suburban communities，just outside major cities．They decided to travel great distances to and from work in exchange for a home in the suburbs．Their cars became a symbol of freedom．

    But today，many people believe they can save money by living in the city．

    Greg Billing is with the Washington Area Bicyclist Association．“When a person makes a change from using a car to using a bike，he／she is saving anywhere between 8 or $9，000 a year．”

    Ralph Buehler says governments save money when people use bicycles．“Building bicycling facilities is much cheaper than building and maintaining road facilities or public transport．”

    Washington，DC has also taken steps to protect bike riders．It approved a safe passing law and created areas on the road between cars and bikes．

    The United States Census Bureau says 4％of the city's workers ride to work by bike．The only city on the East Coast with more bike commuters is New York．

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    Welcome to Orlando! It has a host of attractions and activities. Ready to join the party and plan a visit to O-Town? Just print out our must-see list.

    Universal Orlando's Islands of Adventure

    The addition of The Wizarding World of Harry Potter is on the list of must-visits for theme park lovers. Each of the park's “islands”—Toon Lagoon, Jurassic Park, Marvel Super Hero Island, Seuss Landing and The Lost Continent—is unique!(407-363-8000)

    Gatorland

    It bills itself as “Orlando's best half-day attraction”, for in a city people are limited by their time and money. Catch Gatorland's animals and handler shows in the afternoon. There's a nighttime run as well. Other fun add-ons include the Gator Night Shine. Gatorland is known as a theme park bargain.(407-855-5496)

    Aquatica

    As one of the city's most unique water parks, Aquatica is a wonderful world of water rides and white sand beaches. And if you enjoy a side of fear with your water-park fun, be sure to check out Ihu's Breakaway Falls. This towering slide is not for the weak heart. The less adventurous will still find plenty of fun playing from one big wave pool to another or flowing down the lazy river through a world of unusual fish. You can also watch dolphins underwater. (407-351-3600)

    Warbird Adventures

    Warbird Adventures offers you the opportunity to fly like a hero in World War II in the North American Aviation T-6 Texan(also known as the Harvard). Flights last from 15 minutes to an hour. A visit to the nearby Kissimmee Air Museum is a wonderful way to round out the experience. (407-870-7366)

                                                                                              America's top comic book stores

    New York City, NY － JHU Comic Books

    NYC has a number of impressive comic book stores. While other comic book stores in the city fill their shelves with other products like cards and board games, JHU focuses only on the comics themselves, with shelves filled with great selections of the latest releases and back issues from wall to wall. (32 East 32nd St, 212 — 268 — 7088)

    Austin, TX－Austin Books & Comics

    Opened in 1977, Austin Books &. Comics is one of Texas' biggest and longest running comic book stores. Not only do they sell the latest issues, they also carry many first editions and back issues. Good news is that they often hold regular book purchase discount activities, which means that you'd better consult them before your visit. (5002 N Lamar Blvd, 512－454－4197)

    Washington D. C. － Big Planet Comics

    This store, originally from Georgetown, prefers the more independent, small-press titles as well as stuff from Europe and Japan that your kids probably haven't even heard of, but they also carry the more popular ones. True to its name, BPC has established its own comic book world, with book signing and meet-and-greet events, and their very own, though tiny, comic book publishing house. (1520 U St NW, 202 —342 —1961)

    Portland 9 OR － Floating World Comics

    Floating World Comics is not only a comic book store but a community hosting art shows. Priding itself on cool style, this is an ideal place for comic books, where art books fill shelves just as much as the more mainstream comics. Both the future artists and the comic book lovers in your family will more than appreciate a stopover during your Portland vacation. (400 NW Couch St, 503－241－0227)

    Meeting people from another culture can be difficult. From the beginning, people may send the wrong signal. Or they may pay no attention to signals from another person who is trying to develop a relationship.

    Different cultures stress the importance of relationship building to a greater or lesser degree. For example, business in some countries is not possible until there is a relationship of trust. Even with people at work, it is necessary to spend a lot of time in "small talk", usually over a glass of tea, before they do any job. In many European countries, like the UK or France, people find it easier to build up a lasting working relationship at restaurants or cafe rather than at the office.

    Talk and silence may also be different in some cultures. I once made a speech in Thailand. I had expected my speech to be a success and start a lively discussion, instead there was an uncomfortable silence. The people present just stared at me and smiled. After getting to know their ways better, I realized that they thought I was talking too much. In my own culture, we express meaning mainly through words, but people there sometimes feel too many words are unnecessary.

    Even within Northern Europe, cultural differences can cause serious problems. Certainly, English and German cultures share similar values, however, Germans prefer to get down to business more quickly. We think that they are rude. In fact, this is just because one culture starts discussions and makes decisions more quickly.

    People from different parts of the world have different values, and sometimes these values are quite against each other. However, if we can understand them better, a multicultural environment will offer a wonderful chance for us to learn from each other.

    It is common to see many different kinds of insects while spending time outside in the summer. Some of them do not trouble people and can even add beauty to the natural environment. Other insects can harm the environment or humans. The population of these insects seems to stay large and healthy.

    But scientists say this does not appear to be true for some flying insects that serve an important purpose. There is growing evidence that these insects are decreasing across the world.

    One researcher looking into the present insect population is Doug Tallamy, a professor at the University of Delaware. He remembers walking through Washington D. C., in the past when it was "alive with insects, especially butterflies". Now, he said, "The flying insects are actually gone." Wilson said this point seemed to be proved during a drive he made last year from Boston to Vermont. He was surprised that, during his trip, he counted only one insect that had hit the car's front window. Several other scientists have carried out similar tests by checking how many insects hit their cars while traveling.

    While researchers admit this method is not scientific, they say it can still help them understand the changing flying insect population. There have not been many studies done on the flying insect populations covering large areas. However, some international research suggests a downward turn. In 2006, a group of studies showed that there had been a 14-percent drop in ladybugs(瓢虫) in the United States and Canada from 1987 to 2006. In Germany, a 2017 study found an 82-percent drop in the number of flying insects compared to levels recorded in 1990.

    After the German study, other countries also started looking into the problem. David Wagner of the University of Connecticut says other evidence leads him to believe the findings of the 2017 study are "clearly not a German thing".