Ever get that feeling you're being watched? Well, if you're a dog-owner, you may have a point. Dogs are able to watch people's interactions with one another to determine who holds yummier treats, according to a new study. This study joins others that show dogs are good observers of human behaviors and feelings. It offers evidence that dogs use information not only from people's direct interactions with them, but also their interactions with one another.

    In the study, dogs watched a man ask two women for some of their corns. Both women gave the man corns when he asked, but in response to one woman, the man showed his enthusiasm and said the corns were so delicious. In response to the other woman, he gave the corns back and called them gross（in Spanish；the study was conducted in Argentina）. After these interactions, the man left and an assistant holding the dog let the dog go. While many dogs didn't approach either woman, the dogs that did have a preference tended to prefer the woman with the yummier(美味的) food.

    Other studies of dogs' people-watching ability have found dogs are able to tell the difference between happy and sad faces in their owners. They prefer people who give others food when asked over people who don't give others food. And in one study, dogs turned toward crying people more often than toward talking people.

    So how much do dogs really understand about the humans around them? That's not totally settled yet. In a strange twist to the Argentine study above, when the researchers tried an experiment in which they put two plates of corns on a table and had a man react to each plate, dogs didn't preferentially approach the tastier plate afterward. You could say dogs watch for the interaction between two persons, not just how a person reacts. Yet a previous study found dogs will choose boxes that people reacted to happily, but not boxes people reacted to with a disgusted face.

    Well, either way, you can be sure Fluffs is keeping an eye on you, to the best of her ability. The study was published in the journal PLOS One.

    Dreams can be familiar and strange, fantastical or boring, but some dreams might be connected to the mental processes that help us learn. No one knows for certain why people dream, but some dreams might be connected to the mental processes that help us learn. In a recent study, scientists found a connection between nap-time dreams and better memory in people who were learning a new skill.

    In the study, 99 college students between the ages of 18 and 30 each spent an hour on a computer, trying to get through a virtual maze(迷宫). The maze was difficult, and the study participants had to start in a different place each time they tried — making it even more difficult. They were also told to find a particular picture of a tree and remember where it was.

    For the first 90 minutes of a five-hour break, half of the participants stayed awake and half were told to take a short nap. Participants who stayed awake were asked to describe their thoughts. Participants who took a nap were asked about their dream after sleep — and they were awakened within a minute of sleep to describe their dreams.

    Stickgold, a neuroscientist (神经科学家), to know what people were dreaming about when their eyes weren't moving, during sleep.

    Four of the 50 people who slept said their dreams were connected to the maze. Some dreamed about the music that had been playing when they were working; others said they dreamed about seeing people in the maze. When these four people tried the computer maze again, they were able to find the tree faster than before their naps.

    Stickgold suggests the dream itself doesn't help a person learn — it's the other way around. He suspects that the dream was caused by the brain processes associated with learning.

    All four of the people who dreamed about the task had done poorly the first time, which makes Stickgold wonder if the dreams show up when a person finds a new task particularly difficult. People who had other dreams, or people who didn't take a nap, didn't show the same improvement.

    If a diver surfaces too quickly, he may suffer the bends. Nitrogen (氮) dissolved (溶解) in his blood is suddenly liberated by the reduction of pressure. The consequence, if the bubbles (气泡) accumulate in a joint, is sharp pain and a bent body—thus the name. If the bubbles form in his lungs or his brain, the consequence can be death.

    Other air-breathing animals also suffer this decompression (减压) sickness if they surface too fast: whales, for example. And so, long ago, did ichthyosaurs. That these ancient sea animals got the bends can be seen from their bones. If bubbles of nitrogen form inside the bone they can cut off its blood supply. This kills the cells in the bone, and consequently weakens it, sometimes to the point of collapse. Fossil (化石) bones that have caved in on themselves are thus a sign that the animal once had the bends.

    Bruce Rothschild of the University of Kansas knew all this when he began a study of ichthyosaur bones to find out how widespread the problem was in the past. What he particularly wanted to investigate was how ichthyosaurs adapted to the problem of decompression over the 150 million years. To this end, he and his colleagues traveled the world's natural-history museums, looking at hundreds of ichthyosaurs from the Triassic period and from the later Jurassic and Cretaceous periods.

    When he started, he assumed that signs of the bends would be rarer in younger fossils, reflecting their gradual evolution of measures to deal with decompression. Instead, he was astonished to discover the opposite. More than 15% of Jurassic and Cretaceous ichthyosaurs had suffered the bends before they died, but not a single Triassic specimen (标本) showed evidence of that sort of injury.

    If ichthyosaurs did evolve an anti-decompression means, they clearly did so quickly—and, most strangely, they lost it afterwards. But that is not what Dr Rothschild thinks happened. He suspects it was evolution in other animals that caused the change.

    Whales that suffer the bends often do so because they have surfaced to escape a predator (捕食动物) such as a large shark. One of the features of Jurassic oceans was an abundance of large sharks and crocodiles, both of which were fond of ichthyosaur lunches. Triassic oceans, by contrast, were mercifully shark- and crocodile-free. In the Triassic, then, ichthyosaurs were top of the food chain. In the Jurassic and Cretaceous, they were prey (猎物) as well as predator—and often had to make a speedy exit as a result.

    If anyone had told me three years ago that I would be spending most of my weekends camping. I would have laughed heartily. Campers, in my eyes, were people who enjoyed insect bites, ill-cooked meals, and uncomfortable sleeping bags. They had nothing in common with me.{#blank#}1{#/blank#} 

    The friends who introduced me to camping thought that it meant to be a pioneer.{#blank#}2{#/blank#} We sleep in a tent, cooked over an open fire, and walked a long distance to take the shower and use the bathroom. This brief visit with Mother Nature cost me two days off from work, recovering from a bad case of sunburn and the doctor's bill for my son's food poisoning.

    I was, nevertheless, talked into going on another fun-filled holiday in the wilderness.{#blank#}3{#/blank#} Instead, we had a pop-up camper with comfortable beds and an air conditioner. My nature-loving friends had remembered to bring all the necessities of life.

    {#blank#}4{#/blank#} We have done a lot of it since. Recently, we bought a twenty-eight-foot travel trailer complete with a bathroom and a built-in TV set. There is a separate bedroom, a modern kitchen with a refrigerator. The trailer even has matching carpet and curtains.

    {#blank#}5{#/blank#} It must be true that sooner or later, everyone finds his or her way back to nature. I recommend that you find your way in style.

A.I must say that I have certainly come to enjoy camping.

B.Things are going to be improved.

C.I was to learn a lot about camping since then, however.

D.The trip they took me on was a rough one.

E.After the trip, my family became quite interested in camping.

F. This time there was no tent.

G. There was no shade as the trees were no more than 3 feet tall.

    The United States estimates that about one out of every 10 people on the planet today is at least 60 years old. By 2050, it's projected to be one out of 5. This means that not only will there be more old people, but there will be relatively fewer young people to support them.

    Professor Richard Lee of the University of California at Berkeley says this aging of the world has a great effect on economics. "Population aging increases the concentration of population in the older ages and therefore it is expensive," he said.

    Aging populations consume (消耗) more and produce less. With more people living longer, it could gel expensive. But Mr. Lee says with continuing increases in worker productivity and wise planning, it can be manageable.

    Societies have different methods for caring for the elderly，but each carries a cost Generally, there are three types of support Seniors can live off the wealth they gained when they were younger. They can rely on their family to take care of them, or they can rely on the movement.

    In industrialized nations, governments created publicly-funded (公共资助的) support systems. These worked relatively well until recent years, when aging population growth in places like the United States and Western Europe began to gradually weaken the systems' finances(资金). These nations now face some tough choices. Mr. Lee says the elderly in some of these countries must either receive less money, retire later or increase taxes to make the system continuable.

    Most developing nations haven't built this type of government-funded support, but have instead relied on families to care for their elderly. These nations also generally have a much younger population, which means their situation is not as urgent as more developed nations. But Mr. Lee says that doesn't mean they can pay no attention to the issue. "Third World countries should give very careful thought to this process, to population aging and how it may affect their economies — now, before population aging even becomes a problem," he explained.

    "Cleverness is a gift while kindness is a choice. Gifts are easy—they're given after all. Choices can be hard."

    I got the idea to start Amazon 16 years ago. I came across the fact that the Internet usage was growing at 2300 percent per year. I'd never seen or heard of anything that grew that fast, and the idea of building an online bookstore with millions of titles was very exciting to me. I had just turned 30, and I'd been married for a year. I told my wife that I wanted to quit my job and go to do this crazy thing that probably wouldn't work since most start-ups don't and I wasn't sure what to expect. She told me I should go for it. As a young boy, I had been a garage inventor. I had always wanted to be an inventor, and she wanted me to follow my passion.

    I was working at a financial firm in New York City with a bunch of very smart people and a brilliant boss that I much admired. I went to my boss and told him that I wanted to start a company selling books on the Internet. He took me on a long walk in Central Park，listened carefully to me and finally said, "That sounds like a really good idea，but it would be an even better idea for someone who didn't already have a good job." That logic made some sense to me，and he convinced me to think about it for 48 hours before making a final decision. Seen in that light, it really was a difficult choice，but ultimately, I decided I had to give it a shot. I didn't think I would regret trying and failing. And I suspected that I would always be haunted by a decision to not try at all.

    After much consideration, I took the less secure path to follow my passion, and I'm proud of that choice. For all of us, in the end, we are our choices.