Retired nurse Sue Collins was just beginning the second length of her local pool when her morning swim suddenly became anything but a pleasure.

    Two months ago Sue, 69, who has never suffered from asthma or any other breathing problem in the past, suddenly found herself hard for breath.

    “I felt as if my throat and oesophagus (食道) were closing up,” says Sue.

    Sue is convinced the problem is related to the indoor swimming baths. “I spend half the year in Turkey and swim every day outside in a pool or the sea there and never have this problem,” she says.

    She may be right, because although a trip to the pool is the perfect exercise for many, the chlorine (氯气) used to keep the water free from germs can lead to problems.

    But in most cases it's not the chlorine that causes problems, but the by-products formed when chlorine interacts with other substances — and this is mostly due to people not showering before they enter the pool.

    “This then poisons the water for them and for others,” says Dr. Hull. “The chlorine interacts with sweat and urine(尿素) on the skin and forms by-products called chloramines that float above the surface as a gaseous solution that can be inhaled in.”

    Chloramines are heavier than air so hang over the water where they are easily breathed in. Some believe they may cause lung disorders. A Swedish study in 2013 examining the health of 146 workers at 46 indoor pools found that 17 per cent had airway trouble at work — but no problems at home.

    As Dr. Hull says: ‘People need to remember that showering isn't just for them. It is for the greater good.'

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。

    Tulou, the special residential architecture of Fujian Province was included on the UNESCO's World Heritage List during the 32nd session of the World Heritage Committee in Quebec, Canada.

    In the fourth century, Han Chinese living in the Central Plains area began to migrate south, gradually gathering in Fujian and forming the Hakka communities. As a defence against enemies, the Hakkas chose to live in compact (紧凑的) communities, and the tulou was their preferred houses. Tens of thousands of such earthen structures were constructed in Fujian Province.

    Most tulous are to be found in the valleys, surrounded by high mountains, and some are in the depths of the great mountains. Most are three to four storeys high, and look like circular blockhouses (堡垒). Rooms on the first floor are used as kitchens, rooms on the second floor are used as barns (谷仓), and rooms on the third and fourth floors are for bedrooms and living rooms. For defensive purposes, the rooms on the first floor have no windows.

    Raw materials for the tulou were obtained locally. Their main building material was a mixture of clay, sand, lime and water, and egg whites, brown sugar and rice water were added as adhesive agents (粘合剂). It was then mixed to form the walls. Once they dried, the walls were so hard that driving a nail into them would have been difficult. Fir branches, which are extremely strong and do not rot, were used to strengthen them, and many centuries later they have remained their original look.

    Tulous are located in a region where earthquakes happen frequently, and their circular construction helps them resist the regular shocks.

    The proven design even inspired one famous Peruvian architect, who paid several visits to Yongding, to build a tulou back home. Not long after, an earthquake struck only 10 kilometers away, and while all the houses around the earthen building fell down, his tulou remained.

    Generations of Americans have been brought up to believe that a good breakfast is one of life's essentials. Eating breakfast at the start of the day, we have all been told again, is as necessary as putting gasoline in the family car before starting a trip.

    But for many people the thought of food as first thing in the morning is by no means a pleasure. So despite all the efforts, they still take no breakfast. Between 1977 and 1983, the latest year for which figures are available, the number of people who didn't have breakfast increased by 33 percent-from 8.8 million to 11.7 million-according to the Chicago-based Market Research Corporation of America.

    For those who feel pain or guilt about not earing breakfast, however, there is some good news. Several studies in the last few years indicate that, for adults especially, there may be nothing wrong with not taking breakfast. “Going without breakfast does not affect performance,” said Arnold E. Bender, former professor of nutrition（营养）at Queen Elizabeth College in London, “nor doegiving people breakfast improve performance.”

    Scientific evidence linking breakfast to better health or better performance is surprisingly inadequate, and most of the recent work involves children, not adults. “The literature,” says one researcher, Dr. Ernesto Pollitt at the University of Texas, “is poor.”

    Bus Tours in Washington DC

    The Blossoms Tour In Washington DC

    Duration: 3 hours $56.99

    BEST WAY to Experience the Cherry Blossoms! Each year from mid March to mid April, see the beautiful Cherry Blossoms in Washington DC and get great photos because you'll be led to all the best spots by the best guides. The annual spring bloom in DC is a magical time and this tour promises to provide the very best tour opportunity for you!

    The Lights Night Tour in Washington DC

    Duration: 3 hours $56.33

    Highest-rated Night Tour in DC! The ONLY DC Night Tour where the Tour Guides HOP OFF with you at each stop and tell you about each monument and attraction. HOP aboard the The Lights Night Tour! The best time to take a tour of Washington DC is at night.

    The Best Minibus Tour in Washington DC

    Duration: 3 hours $ 46.92

    See all the key attractions DC has to offer in a 3-hour format. You will learn all about the history and trivia (琐事) that surrounds Washington and visit the major monuments and attractions DC has to offer.

    Please Note: Rates for this tour vary by day of the week. When you choose your specific date on the availability calendar, the rates for that date will be displayed.

Best Mount Vernon & Arlington Cemetery Tour from Washington DC

    Duration: 6 hours $ 78.96

    See Arlington Cemetery, Old Town Alexandria and George Washington's Mount Vernon Estate on this small group bus tour from Washington DC. Your tour guide will accompany you through Mount Vernon, telling you about all of the attractions there and the history of George Washington's home on the Potomac River.

    Parents should ban electronic media during mealtimes and after bedtime as part of a comprehensive "family media use plan", according to new recommendations from the American Academy of Pediatrics. "Excessive media use is associated with obesity, poor school performance, aggression and lack of sleep", said Marjorie Hogan, co-author of the new policy.

    Families should have a no-device rule during meals and after bedtime, the guidelines say. Parents should also set family rules covering the use of the Internet, cellphones, including, perhaps, which sites can be visited, and who can be called. The policy also restated the existing recommendations: Kids should limit the amount of screen time for entertainment to less than two hours per day; children younger than 2 shouldn't have any TV or Internet exposure. Also, televisions and Internet-accessible devices should be kept out of kids' bedrooms.

    Doctors say parents need to obey the family rules, too, to model healthy behavior. That, some say, may be the toughest part. "If you go to any restaurant, Family 3.0 is Mom and Dad on their devices and the kids on theirs", says Donald, a pediatrician and an AAP spokesman. "Who is talking to each other?"

    Children aged from 8 to 18 spent an average of 7 hours and 38 minutes a day consuming media for fun, including TV, music, video games and other content in 2009, according to a 2010 report from the Kaiser Family Foundation. The report was based on a survey of 2002 third through twelfth graders, 702 of whom completed a seven-day media use diary. That was up about an hour and 17 minutes a day from five years earlier. About two-thirds of 8 to 18-year-olds said they had no rules on the amount of time they spent watching TV, playing video games or using the computer, the Kaiser report found.

    Use of mobile devices by young kids has soared. A new report from Common Sense Media, a child-advocacy group based in San Francisco, found that 17% of children 8 and younger use mobile devices daily, up from 8% in 2011.