Using too much water or throwing rubbish into our rivers are clear ways that humans can put our water supply in danger , but we also affect our water supply in less obvious ways. You may wonder how paving(铺砌) a road can lead to less useable fresh water. A major part of the water we use every day is groundwater. Groundwater does not come from lakes or rivers. It comes from underground. The more roads and parking lots we pave ，the less water can flow into the ground to become groundwater.

    Human activity is not responsible for all water shortages(短缺). Drier climates are of course more likely to have droughts(干旱) than areas with more rainfall, but in any case, good management can help to make sure there is enough water to meet our basic needs.

    Thinking about the way we use water every day can make a big difference, too In the United States , a family of four can use 1.5 tons of water a day! This shows how much we depend on water to live, but there's a lot we can do to lower the number.

    You can take steps to save water in your home. To start with use the same glass for your drinking water all day. Wash it only once a day. Run your dishwasher (洗碗机)only when it is full 。Help your parents fix any leaks in your home. You can even help to keep our water supply clean by recycling batteries instead of throwing them away.

    Princeton University is a vibrant (充满生机的) university. It is the fourth oldest college in the United States and an independent institution that provides undergraduate and graduate instruction in the arts and humanities, social sciences, natural sciences, and engineering. As a well-known research university, Princeton seeks to achieve the highest levels in the discovery and spread of knowledge and understanding. At the same time, Princeton is different among research universities in its commitment to undergraduate teaching.

    Academics

    Faculty (教员), including full time, part time and visiting: 1,238 (spring 2016)

Undergraduate student-to-faculty rate: 5:1

    Departments: 36

    Schools within the University: School of Architecture, School of Engineering and Applied Science, Woodrow Wilson School of Public and International Affairs

    Library

    Princeton University Library consists of the Firestone Library and nine buildings across campus. The library's collections include more than 8 million books and impressive rare books, prints and other materials that require special handling. The library's extensive electronic resources include databases and journals, images and digital maps. Exhibitions of the library are free and open to the general public.

    Campus Life

    A vast range of cultural9 educational, athletic and social activities are available to Princeton students. Getting involved in campus life is the quickest way to become a part of the University community, and to create one's own Princeton experience. Campus life activities are built around the concepts of encouraging each community member to display his or her talents and to learn to respect all members of our community.

    Aid Program

    Our aid program is designed to encourage all qualified students—regardless of financial circumstances-to consider applying for admission to Princeton. Any family who feels they may need help to pay for a Princeton education is welcome to apply for aid.

    For more information, please visit: http://www. Princeton.edu.

    I grew up with a group of pets. As a mother, I was determined to provide my daughter with the same joyful experiences. Indeed, by the time my daughter was in elementary school, our house was known as "the neighborhood zoo". Now that she is a teenager, we've reduced the number of animals in our home, but we still live with two dogs. I can't imagine life without them.

    Regardless, I have become increasingly uncomfortable with the word "pet". When I came upon the conclusion by the University of Tennessee zoologist Gordon Burghardt that the best we can do for pets is a life of "controlled deprivation (剥夺)", I wished I had never bought Lizzy, our leopard gecko(豹纹守宫). I felt a pit in my stomach when I learned that Lizzy's constant clawing at the glass wall of her tank was most likely a signal of stress. It is perhaps not surprising that she died after only two years, despite our efforts to give proper care.

    The problems with the various small creatures we put into cages and tanks are relatively clear-­cut. More challenging moral questions, in my view, arise in relation to our closest furry friends: dogs and cats. Unlike animals that must spend their entire life in a cage or that must struggle to adapt to a human environment, most cats and dogs have it pretty good. Yet it is likely that our dogs and cats may be suffering in ways we don't readily see, because even the most well meaning owner doesn't always provide what an animal needs.

    It may be hard to recognize the harmful aspects of pet keeping when all we hear is how beloved pets are and how happy they are to be in our company. Advertisements showing golden­-haired children playing with golden-­haired puppies and YouTube videos of cats doing funny things make pet keeping look ever so precious.

    Yet if we really care about animals, we ought to know animals are not toys — they are living, breathing, feeling creatures.

    Chocolate is good for your heart, skin and brain. Usually, people think that chocolate is bad for their health. They describe chocolate as “something to die for” or say “death by chocolate”. Now they should bite their tongues! Evidence is showing that some kinds of chocolate are actually good for you in the following ways:

    A happier heart

    Scientists at Harvard University recently examined 136 studies on cocoa—the main ingredient in chocolate and found that it does seem to strengthen the heart．Studies have shown heart benefits from increased blood flow. These benefits are the result of coca's chemicals, which seem to prevent both cell damage and inflammation (炎症)．

    Better blood pressure

    If yours is high, chocolate may help. Jeffrey Blumberg from Tufts University recently found that people with high blood pressure who ate 3.5 ounces of dark chocolate per day for two weeks saw their blood pressure drop quickly.

    Muscle magic

    Chocolate milk may help you recover after a hard workout (锻炼). In a small study at Indiana University, people who drank chocolate milk between workouts did better on a tiredness test than those who had some sports drinks.

    Better for your skin

    German researchers gave 24 women a half-cup of special cocoa every day. After three months, the women's skin was moister (滑润的) and smoother. The research shows that chocolate helps protect and increase blood flow to the skin, improving its appearance．

Brain gains

    It sounds almost too good to be true, but research suggests that chocolate may improve your memory, attention span, reaction time, and problem-solving by increasing blood flow to the brain．

    As any plane passenger will confirm, a crying baby is almost impossible to ignore, no matter how hard you try. Now scientists believe they may have worked out why. A baby's cry pulls at the heartstrings(扣人心弦)in a way while other cries don't, researchers found.

    Researchers found that a baby's cry can trigger unique emotional responses in the brain, making it impossible for us to ignore them—whether we are parents or not. Other types of cries, including calls of animals in great pain, fail to get the same response…suggesting the brain is programmed to respond specifically to a baby's cry.

A team of Oxford University scientists scanned the brains of 28 men and women as they listened to a variety of calls and cries. After 100 milliseconds — roughly the time it takes to blink (眨眼) —two parts of the brain that respond to emotion lit up. Their response to a baby's cry was particularly strong. The response was seen in both men and women—even if they had no children.

    Researcher Dr Christine Parsons said, "You might read that men should just notice a baby and step over it and not see it, but it's not true. There is a special processing in men and women, which makes sense from an evolutionary(演化的)view that both men and women would be responding to these cries." The study was in people who were not parents, yet they are all responding at 100ms to these particular cries, so this might be a fundamental response present in all of us regardless of parental status.

    Fellow researcher Katie Young said it may take a bit longer for someone to recognize their own child's cries because they need to do more "fine-grained analysis". The team had previously found that our reactions speed up when we hear a baby crying. Adults performed better on computer games when they heard the sound of a baby crying than after they heard recordings of adults crying.

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