Over the last week, a "poisonous kale（甘蓝菜）" theory has been going widespread after an article warned that the vegetable was associated with a variety of medical conditions. It's time to separate fear from fact on the health benefits of kale.

    As a member of the cabbage family, kale is low in calories and rich in nutrients and minerals, especially vitamin A,C and K. Consumed for thousands of years, it's been a health plus for millions of eaters throughout the world.

    However, numerous web articles have reported on some evidence offered by a medicine researcher. The researcher found that thallium（铊）was detected in a few people who were heavy consumers of kale. Thallium is a heavy metal often found in trace amounts（微量）in soil and minerals. His conclusion was that these medical conditions were connected to the impact that trace amounts of thallium detected in some kale samples had on the body.

    I don't think the conclusion is based on a strict scientific basis. It's essential to point out that the original report was in a web magazine, not a scientific journal which is subject to peer review by other scientists. A scientific review includes a careful evaluation of how the findings and conclusions were made. Certain factors are critical before an evidence-based conclusion can be made, such as: how many people were in a study; how well controlled were other factors; how much kale was consumed and for how long; how much thallium was in the kale.

    It is a fact that kale and other vegetables can absorb thallium from the soil. But the ability for a plant to absorb traces of a chemical does not automatically make it harmful to your health. And even finding measurable amounts of thallium in someone's body doesn't imply that the thallium is causing an ill health effect, according to the CDC.

    But we can still learn a lesson from this. Plants grow in soil. Growers must continue to be careful in monitoring the quality of their soil. And what about consumers? Eat your kale—and include lots of other colorful fruits and vegetables. As with all things in nature, variety is key for good health.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    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.

    Britain's pub landlords (酒吧店主) are looking with a worried eye to the UK Chancellor's budget for fear that the annual tax gathering round will strike another blow to a traditional industry already reeling (蹒跚). Thousands of pubs have closed since the financial crash in 2007.

    The Plough, which was once a coaching house for travelers, has been serving Britain's famous warm beer since the days of Shakespeare. Now it is under threat too. "Yeah. So many pubs have been closed over the last few years even in this area," said Derek O'Neil, the manager of The Plough Pub.

    Many reasons are the cause—a ban on smoking in public, severe laws against drinking and driving and high taxes have all combined to kill off nearly 10,000 pubs in the last seven years, according to the British Beer and Pub Association. With the closures, pubs are being redeveloped. Many have turned into supermarkets, where the beer is sometimes cheaper.

      Britain's pubs continue to play an important part in the UK economy, selling thousands of different beers and employing more than a million people. The reality, though, is pubs are suffering something of a hangover (遗留物). In the last 15 years the amount of beer sold in pubs has fallen by eight million barrels to just under 36 million a year. Pub landlords want tax breaks (税务减免).

    "People have less money in their pockets, so they can't go out and spend it and habits are changing—so much alcohol is nowadays drunk at home," said Brigid Simmonds, Chief Executive of the British Beer and Pub Association. "Yeah, I miss the pubs where there's a lot of character, especially 30 years ago. You know there was great fun in them."

While pubs are still much loved, they're discovering that love isn't enough to survive 21st century economics.

    The news of Harper Lee's second novel broke the internet. Go Set a Watchman would be published in July. Lee became a recluse (隐士)after the publication of her first book, To Kill a Mockingbird, in 1960. Although the author has been out of the public eye for more than 50 years, the wave that followed the announcement showed her novel's beloved place in the American literary works.

    In 1991, The Book of the Month Club and the library of Congress conducted a survey that made readers identify books that had made a difference in their lives. Lee's book followed only The Bible. Alongside the works of Shakespeare and Twain, To Kill a Mockingbird remains one of the most widely taught books nationwide, reaching an estimated 70% of American public schools. What makes it such a perfect read for young people?

    English class is a place where young Americans come to know themselves. In the folds of dusty books, students can make contact with humanity beyond the superficial(肤浅的) conversations of the school hallways. Literature promises relief, a place to figure out one's problems and get to know oneself better.

    To Kill a Mockingbird particularly distinguishes itself in this regard. It speaks in child's voice without treating its readership as children. People have called it an 'impossible' achievement, a children's book penned in the prose(散文) of a well-educated adult—it's unlikely that a child like Scout could exist in the real world. But that's exactly what makes it such a charming read for young people. It alludes to (转弯抹角地说到)the consciousness of a well-educated adult going through difficult realities, but shows it through the light and playful voice of a curious little girl.

    Fireworks are exciting, but also hard to control. The Chinese artist Cai Guoqiang, though, has developed a way to harness the visual and physical power of fireworks to make art He recently used them to create a burning sculpture that stretched high into the sky. Guoqiang fittingly named the work Sky Ladder.

    Guoqiang built Sky Ladder by making a frame out of metal. He coated the frame with gunpowder, the main chemical material in fireworks.

    The artist tried one end of the frame to the ground and attached a large weather balloon to the other end. The balloon was filled with helium — a gas that is lighter than air. When released, the balloon floated upward, pulling the top of the ladder 500 meters into the sky. That's higher than the top of the Empire State Building.

    Guoqiang set fire to the bottom of the ladder, and the crackling（啪啪作响） flames raced skyward up the frame. The sculpture burned for two-and-a-half minutes before its flames began to die out from the bottom up.

    Dealing with explosive (炸药）is challenging, and conditions had to be perfect for Guoqiang to achieve his desired effect. He first attempted Sky Ladder in 1994, but bad weather prevented him from successfully completing the work. Guoqiang put Sky Ladder aside so that he could work on other projects, perhaps most famously the fireworks display that opened the 2008 Beijing Olympic Games.

    Finally, after two more failed attempts, Guoqiang successfully sent his flaming ladder skyward last year. He presented Sky Ladder in his hometown, a quiet fishing village near Huiyu Island, Quanzhou. He offered the work as a gift to his 100-year-old grandmother, other family members, his friends and his town.

    “Behind Sky Ladder lies a clear childhood dream of mine, "Guoqiang explains. “Despite all life's twists and turns, I have always been determined to realize it. The ladder rose toward the morning sun, carrying hope. For me, this not only means a return, but also the start of a new journey."

    With about 100,000 sea animals being choked or injured by plastic every year, the danger produced by the billions of pieces of plastics in our oceans is well-known. However,    given that most of the micro-plastics measure less than 0.5mm, collecting them is a challenge.

    Now, some Dutch environmentalists have created a floating park to catch plastic waste before it reaches the open seas and breaks down. The large floating park is the result of a five-year effort of the Wageningen University and Research, WHIM Architecture, and etc. The team's leader said, "We began by developing a 'plastic fisher(渔船). Fitted with two folding arms with extension of several feet into the water, it uses a net to catch bottles, and any other garbage that floats past."

    The portable equipment took a year and a half to be perfect. It was then placed at the edge of the harbor to collect the urban garbage accumulated in the Meuse, a major European river, which rises in France and passes through Belgium and the Netherlands before it goes into the North Sea. Since Rotterdam's NieuweWaterweg canal links the river the North Sea, it's the ideal place to catch the "fresh" plastic waste before it disappears into the open waters and breaks down.

    The waste collected by the "plastic fisher" was then made into some hexagonal (六边的) floats which were connected to create the floating park. Some of the blocks are open to visitors, while others house various types of plants and even trees for nesting birds. The underside of the floats provides a suitable environment for sea creatures like fish. The environmentalists say the blocks can also be used to build sports areas and public walkways.

    The floating park has achieved great success. The team has launched a similar project in Indonesia to deal with local pollution. They worked with the local government and colleges which have given great support. And the team wants to spread their idea to some other places. When more and more people have better understanding of the project, more countries worldwide will know the advantages of the project and try similar outstanding approaches.