1. (2018高二下·宁德期末) 阅读理解

    If you're new to San Francisco, paying the city a visit, or simply looking for a new playground for you and your dog, here are four of the finest dog parks in San Francisco.

    Corona Heights Dog Park

    Often visited by residents from all over the city because of its nearness to the Randall Museum, Corona Heights Dog Park offers pets and owners breathtaking view after a steep hillside climb, and a fenced dog area that allows dogs to let loose without a leash（狗链）. Owners will also enjoy the playground, tennis courts and basketball courts.

    Dolores Dog Park

    The grounds of Dolores Park once served as camps for those who were left homeless by the 1906 earthquake, but now are often visited by crowds of Mission District people. Four-legged friends can also wander about carefree off-leash while making friends with other members of the doggie community.

    Pine Lake Dog Park

    Famous for its place as a rest stop for hundreds of species of birds to fly to and from warmer climates, Pine Lake Park is also prized by city dogs and their owners for their nice hiking paths, picturesque lake suited for swimming, and off-leash area on the park's west end that lets dogs run free.

    Buena Vista Dog Park

    With a history of 146 years, Buena Vista Park is San Francisco's oldest park. Dogs and owners with plus energy will love burning it on this park's steep paths and winding staircases. Dog owners should have good control over their dogs, as it's quite easy for dogs to get separated when going through Buena Vista's many twists and turns.

As we age, even if we're healthy, the heart just isn't as efficient in processing oxygen as it used to be. In most people the first signs show up in their 50s or early 60s. And among people who don't exercise, the changes can start even sooner.

"Think of a rubber band. In the beginning, it is flexible, but put it in a drawer for 20 years and it will become dry and easily broken," says Dr. Ben Levine, a heart specialist at the University of Texas. That's what happens to the heart. Fortunately for those in midlife, Levine is finding that even if you haven't been an enthusiastic exerciser, getting in shape now may help improve your aging heart.

Levine and his research team selected volunteers aged between 45 and 64 who did not exercise much but were otherwise healthy. Participants were randomly divided into two groups. The first group participated in a program of nonaerobic (无氧) exercise—balance training and weight training—three times a week. The second group did high-intensity aerobic exercise under the guidance of a trainer for four or more days a week. After two years, the second group saw remarkable improvements in heart health.

"We took these 50-year-old hearts and turned the clock back to 30-or 35-year-old hearts," says Levine. "And the reason they got so much stronger and fitter was that their hearts could now fill a lot better and pump (泵送) a lot more blood during exercise." But the hearts of those who participated in less intense exercise didn't change, he says.

"The sweet spot in life to start exercising, if you haven't already, is in late middle age when the heart still has flexibility," Levine says. "We put healthy 70-year-olds through a yearlong exercise training program, and nothing happened to them at all."

Dr. Nieca Goldberg, a spokeswoman for the American Heart Association, says Levine's findings are a great start. But the study was small and needs to be repeated with far larger groups of people to determine exactly which aspects of an exercise routine make the biggest difference.

The United States rose to global power on the strength of its technology, and the lifeblood that technology has long been electricity. By providing long-distance communication and energy electricity created the modern world. Yet properly understood, the age of electricity is merely the second stage in the age of steam which began a century earlier.

It is curious that on one has put together a history of both the steam and electric revolutions." writes Maury Klein in his book The Pore Makers, Seam, Electricity and the Men Invented Modern America. Klein, a noted historian of technology spins a narrative (叙述) so lively that at times it reads like a novel

The story begins in the last years of the 18th century in Scotland, where Watt perfected "the machine that changed the world". Klein writes/'America did not invent the steam engine, but once they grasped its passwords, they put it to more uses than anyone else.

Meanwhile, over the course of 19th century, electricity went from mere curiosity to a basic necessity. Morse invented a code for sending messages over an electromagnetic circuit Bell then gave the telegraph a voice. Edison perfected an incandescent bulb (白炽灯泡) that brought electric light into the American home.

Most importantly, Edison realized that success depended on mass electrification, which he showed in New York City. With help from Tesla, Westinghouse's firm developed a system using alternating current (交流电), which soon became the major forms of power delivery.

To frame his story, Klein creates the character of Ned, a fictional witness to the progress brought about by the steams and electric revolutions in America during one man's lifetime. It's a technique that helps turn a long narrative into an interesting one.

Researchers say they have translated the meaning of gestures that wild chimpanzees (黑猩猩) use to communicate. They say wild chimps communicate 19 specific messages to one another with a "vocabulary" of 66 gestures. The scientists discovered this by following and filming groups of chimps in Uganda, and examining more than 5,000 incidents of these meaningful exchanges.

Dr Catherine Hobaiter, who led the research, said that this was the only form of intentional communication to be recorded in the animal kingdom. Only humans and chimps, she said, had a system of communication where they deliberately sent a message to another group member.

"That's what's so amazing about chimp gestures," she said. "They're the only thing that looks like human language in that respect. ”

Although previous research has shown that apes and monkeys can understand complex information from another animal's call, the animals do not appear to use their voices intentionally to communicate messages. This was a significant difference between calls and gestures, Dr Hobaiter said.

Chimps will check to see if they have the attention of the animal with which they wish to communicate. In one case, a mother presents her foot to her crying baby, signaling:" Climb on me. " The youngster immediately jumps on to its mothers back and they travel off together. "The big message from this study is that there is another species (物种) out there. that is meaningful in its communication, so that's not unique to humans," said Dr Hobaiter.

Dr Susanne Shultz, an evolutionary biologist from the University of Manchester, said the study was praiseworthy in seeking to enrich our knowledge of the evolution of human language. But, she added, the results were "a little disappointing".

"The vagueness of the gesture meanings suggests either that the chimps have little to communicate, or we are still missing a lot of the information contained in their gestures and actions," she said. "Moreover, the meanings seem to not go beyond what other animal convey with non-verbal communication. So, it seems the gulf remains. "