Charlotte Heffelmire was home in Vienna,Va.,for Thanksgiving break from the Air Force Academy when she saw that her father had gotten stuck under the pickup truck he'd been working on.

    "I was on my back,face up,and I was trying to get some brake lines when apparently the jack（千斤顶）slipped and fell down on me,"her dad,Eric Heffelmire,told WUSA9.Gasoline spilled（溢出）and caught fire,and he knew he was in trouble."I thought they 'd be pulling out a dead body later in the evening."

    After his struggling for 10 minutes,his barefoot teenage daughter came running into the garage."I felt the weight shift,and I said,'You almost got it.'and then it was just UGHHHRRR,and suddenly I'm pulled out,"Eric told NBC4.

    Even Charlotte,120 pounds and 5-foot-6,isn't sure where her power came from."It was some crazy strength, "she told WUSA9.

    Realizing the burning truck could set her house on fire at any moment,Charlotte jumped into the truck and drove it out of the garage."I didn't want the entire house to explode with the truck,so I started the truck,put it in four-wheel drive,and managed to drive it with three wheels,"she said.

    Then she went inside the house to grab her baby sister and got her grandmother out of the house too."I just did what I had to do,so I don't feel like a big hero or anything,"Charlotte said.Her local fire department,Fairfax County Fire and Rescue,felt differently,awarding her the Citizen Lifesaving Award.

    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)

    Weighing too much can damage your health, and obesity is a growing problem for both kids and adults around the world. Sleep might be one answer to the problem. A new study has found that elementary school students who slept too little were more likely to gain pounds.

    Past studies have shown a link between sleeping less and weighing more, but scientists have had a tough time determining "which came first, the chicken or the egg," says Julie C. Lumeng of the university of Michigan in Ann Arbor. In other words, it hasn't been clear whether kids who weigh too much have trouble sleeping, or whether sleeping less leads to weight gain. Both scenarios (可能出现的情况) seemed equally possible.

    To get a better idea of which causes which, Lumeng and her colleagues interviewed the parents of 785 third graders from around the United States. The parents answered questions about how well their kids slept that year. Three years later, the parents answered the same questions. By sixth grade, 18percent of kids involved in the study were obese.

    The scientists found no relationship between weight and the students' race or gender. It also didn't matter how strict their parents were, or whether they were boys or girls. Obesity struck all of these groups equally. Instead, sleep seemed to be the key factor. Over the three years of study, the children averaged a healthy 9. 5 hours of sleep a night. Some kids, however, slept a lot more or less than others.

    For the sixth graders, every hour of sleep above the 9. 5houraverage was linked to a 20 percent lower risk of being obese. Sleep appeared doubly important for the third graders. Every extra hour of sleep they got was linked to a 40 percent drop in obesity.

    Like a tired marriage, the relationship between libraries and publishers has long been dull. E-books, however, are causing heartache. Libraries know they need digital wares, but many publishers are too cautious about piracy (盗版）and lost sales to co-operate. Among the big six, only Random House and Harper Collins license e-books with most libraries.

    Publishers are wise to be nervous. Owners of e-readers (电子阅读器）are exactly the customers they need: book-lovers with money. If these people switch to borrowing e-books instead of buying them, what then? Electronic borrowing is awfully convenient. Unlike printed books, which must be checked out and returned to a physical library miles from where you live, book files can be downloaded at home. The files disappear from the device when they are due.

    E-lending is not simple, however. There are lots of different and often incompatible (不兼容的)e-book formats, devices and licenses. Most libraries use a company called OverDrive，which secures rights from publishers and provides e-books and audio files in every format. Yet publishers and libraries are worried by OverDrive's global market dominance, as the company can control fees and conditions. Publishers were annoyed when OverDrive cooperated with Amazon, the world's biggest online bookseller，last year. Owners of Amazon's Kindle e-reader who want to borrow e-books from libraries are now redirected to Amazon's website, where they must use their Amazon account to secure a loan.

    According to Pew, an opinion researcher, library users are a perfect for market for Amazon. Late last year Amazon introduced its Kindle Owners' Lending Library, which lets its best customers borrow free one of thousands of popular books each month.

    Library supporters argue that book borrowers arc also book buyers and that libraries are vital spaces for readers to discover new work. Many were cheered by a recent Pew survey, which found that more than half of Americans with library cards say they prefer to buy their e-books.

    So publishers keep adjusting their lending arrangements in search of the right balance.

    Random House raised its licensing prices earlier this year, and Harper Collins limits libraries to lending its titles 26 times.

How Much Can We Afford to Forget?

    In 2018, Science magazine asked some young scientists what schools should teach students. Most said students should spend less time memorizing facts and have more space for creative activities. As the Internet grows more powerful, students can access(获得)knowledge easily. Why should they be required to carry so much of it around in their heads?

    Civilizations(文明)develop through forgetting life skills that were once necessary. In the Agricultural(农业的)Age, a farmer could afford to forget hunting skills. When societies industrialized, the knowledge of farming could be safe to forget. Nowadays, smart machines give us access to most human knowledge. It seems that we no longer need to remember most things. Does it matter?

    Researchers have recognized several problems that may happen. For one, human beings have biases (偏见), and smart machines are likely to increase our biases. Many people believe smart machines are necessarily correct and objective, but machines are trained through a repeated testing and scoring process. In the process, human beings still decide on the correct answers.

    Another problem relates to the case of accessing information. When there were no computers, efforts were required to get knowledge from other people, or go to the library. We know what knowledge lies in other brains or books, and what lies in our heads. But today, the Internet gives us the information we need quickly. This can lead to the mistaken belief — the knowledge we found was part of what we knew all along.

    In a new civilization rich in machine intelligence, we have easy access to smart memory networks where information is stored. But dependency on a network suggests possibilities of being harmed easily. The collapse of any of the networks of relations our well-being(健康)depends upon, such as food and energy, would produce terrible results. Without food we get hungry; without energy we feel cold. And it is through widespread loss of memory that civilizations are at risk of falling into a dark age.

    We forget old ways to free up time and space for new skills. As long as the older forms of knowledge are stored somewhere in our networks, and can be found when we need them, perhaps they're not really forgotten. Still, as time goes on, we gradually but unquestionably become strangers to future people.

Ivan Pavlov was a Russian physiologist (生理学家) best known for his discovery of classical conditioning (经典条件反射). During his studies on the digestive systems of dogs, Pavlov found that the animals salivated (流口水) naturally upon the presentation of food. However, he also noticed that the animals began to salivate whenever they saw the white lab coat of an experimental assistant. By associating the presentation of food with the lab assistant, he finally found that a dog would salivate to the presence of a stimulus (刺激物) other than food. He called this response a conditional reflex.

Ivan Pavlov was born in a small village in Ryazan. Russia, where his father was the village minister. His earliest studies were focused on theology (神学), but reading Charles Darwin's On the Origin of Species had a powerful influence on his future interests. He soon stopped his religious studies and devoted himself to the study of science at the University of Saint Petersburg. Pavlov's interests were the study of physiology and natural sciences. He helped found the Department of Physiology at the Institute of Experimental Medicine and continued to manage the program for the next 45 years.

Pavlov received much praise for his work. He worked in the Russian Academy of Science and won the 1904 Nobel Prize in Physiology. The Soviet government also offered lots of support for Pavlov's work, and the Soviet Union soon became a leading center of research on physiology. While Ivan Pavlov was not a psychologist, and reportedly disliked the field of psychology, his work had a major influence on the field, particularly on the development of behaviorism. His discovery and research on reflexes influenced the growing behaviorist movement. and Pavlov's discovery had a major influence on many thinkers, such as John B. Watson.