Nowadays people are putting our water supply in danger, because they use too much water or throw rubbish into the river. You may wonder how paving(铺砌) a road can lead to less usable fresh water. A major part of thewaterweuse 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 morerainfall，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.

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。

     “Let's have a journey. Why not fly out and meet me, Dad?” I say one day.

    My father had just retired after 27 years as a manager for IBM. His job filled his day, his thoughts, and his life. While he woke up and took a warm shower, I screamed under a freezing waterfall in Peru. While he tied a tie and put on the same Swiss watch, I rowed a boat across Lake of the Ozarks.

    My father sees me drifting aimlessly, nothing to show for my 33 years but a passport full of funny stamps. He wants me to settle down, but now I want him to find an adventure.

    He agrees to travel with me through the national parks. We meet four weeks later in Rapid City.

    “What's our first stop？” asks my father.

    “What time is it？”

    “Still don't have a watch？”

    Less than an hour away is Mount Rushmore. As he stares up at the four Presidents carved in granite(花岗岩), his mouth and eyes open slowly, like those of a little boy.

    “Unbelievable,” he says. “How was this done？”

    A film in the information center shows sculptor Gutzon Borglum devoted 14 years to the sculpture and then left the final touches to his son.

    We stare up and I ask myself, “Would I ever devote my life to anything？”

    No directions, no goals. I always used to hear those words in my father's voice. Now I hear them in my own.

    The next day we're at Yellowstone National Park, where we have a picnic.

    “Did you ever travel with your dad？” I ask.

    “Only once,” he says. “I never spoke much with my father. We loved each other — but never said it. Whatever he could give me, he gave.”

    That last sentence — it's probably the same thing I'd say about my father. And what I'd want my child to say about me.

    In Glacier National Park, my father says, “I've never seen water so blue.” I have, in several places of the world. I can keep traveling, I realize — and maybe a regular job won't be as dull as I feared.

    Weeks after our trip, I call my father.

    “The photos from the trip are wonderful,” he says. “We've got to take another trip like that sometime.”

I tell him I've decided to settle down, and I'm wearing a watch.

A typical school day in the UK starts around 8:30 am. This is often even earlier elsewhere in the world, with students sitting down to their first lesson at 7:30 am in the US. The average teenager ideally needs eight to nine hours' sleep each night, but in reality a lot of teenagers struggle to get this much. A lot of the problems arise because our sleep patterns are not fixed, and they change as we grow.

So a later school start time could help to solve this problem, by ensuring to get their eight plus hours of sleep and react properly to their body's natural rhythms (规律). There has been a general shift over the past 25 years to shorten the school day. This is not at the cost of teaching time (which has remained constant) but at the cost of natural breaks, which has led to reduced lunch time and lesson breaks.

Later start times could help teens' grades and health. This is mainly because it makes the management of children easier. Supervising (监管) hundreds of children “playing” requires effective staffing (人员配备). And there is always the fear that behavior worsens during breaks. So the theory goes that having them in class and strictly supervised must be better.

    But this means that students barely have enough time to absorb what they were doing in maths before suddenly they are thrust into ancient history. And teaching staff also transit from one class to another, with hardly a rest or time to refocus.

    Clearly rethinking the school day could benefit everyone involved. Anyway, it could also lead to better achievement in teenagers and less of a struggle for parents in the mornings. For teachers, it could also mean a less stressful day all around and what could be better than that?

    One day a mime(哑剧演员) is visiting the zoo and tries to earn some money as a street performer. As soon as he starts to draw a crowd, a zookeeper pulls him into his office. The zookeeper explains that the zoo's most popular attraction, a gorilla(大猩猩), has died suddenly and the keeper fears that attendance(出席人数) at the zoo will fall off. He offers the mime a job to dress up as the gorilla. The mime accepts.

    The next morning the mime puts on the gorilla suit and enters the cage before the crowd comes. He soon discovers he can sleep, play and make fun of people and he draws bigger crowds than he ever did as a mime — the job he likes but loses.

    However, with days going by, he begins to notice that the people are paying more attention to the lion in the cage next to his. Not wanting to lose the attention of his audience, he climbs to the top of his cage, crawls across a partition(隔墙), and dangles(悬挂) from the top to the lion's cage. The lion gets angry at this. The scene is a fuel to the crowd.

    At the end of the day he is given a raise for being such a good attraction — well, this continues for some time. The crowds grow larger, and the mime's pay keeps going up.

    Then one day when he is dangling over the lion he slides and falls. The mime is terrified. He starts screaming “Help me!”, but the lion is quick. The mime soon finds himself flat on his back looking up at the angry lion and the lion says, “Shut up you fool! Do you want to get us both fired?”

    The best bikes for the beginners

    When it comes to purchasing your first bike, the choice is endless, making it tough to know what to go for. Here are the best buys on the market right now.

    Boardman CX Comp

    This is a cross-country bike, and it's so versatile(多用途的)that you can handle any terrain(地势)on it, making it a great choice for those wanting to try various cycling subjects. If you leave on the thick tires it comes with, it can ride on various paths and can even handle some less demanding mountain bike routes. Alternatively, put on thin, slick tires and treat it as a road bike. It has basket and comes with Shimano Sora gears(齿轮), which are outstanding for its price.

    $650, Halfords

    Planet X RT-58 v2

    Planet X is based in Yorkshire, which means you'd probably have to buy this bike without seeing it. But it's worth it, because this is an excellent machine at a lower price. Planet X is a highly rated manufacture and this model comes with Shimano Sora gears.

    $439, Planet X

    Specialized Allez ES

    Specialized is one of the biggest and most popular brands in cycling, and this is its hugely popular primary road bike. It comes with solid components from front to back and you'll look great out on the road.

    $575, Evans Cycles

    Boardman Road Team Carbon

    If you can push budget further still, this bike is worth the extra investment. The frame is made entirely from carbon, which is lighter, faster and more comfortable than the composition metal models above and gives you an all-round more enjoyable ride. It also means that if you get really serious about cycling, you don't have to upgrade as quickly as you would with a cheaper bike.

    $800, Halfords

    Devon Gallagher, a college graduate from Philadelphia, wants the world to know exactly here she's been during her worldwide vacation in a special way.

    The traveler, who was born with a bone disease, had her right leg amputated(k)at the age of four. Although the amputation caused setbacks for Gallagher early on, she now sees it as nothing short of inspiration for living her best life.

    To spread that message, Gallagher has taken to social media, where she shares photos of her travels across the globe, but instead of simply using a geo-tag, she writes her location across her artificial leg before taking a picture.

    Now she has been taking pictures across the Continent, which show her cycling over the canal in Amsterdam relaxing on a wall overlooking the city of Barcelona, posing with a waffle in Brussels, taking in the spectacular Parthenon temple in Athens and enjoying a river cruise in Budapest, all with the well-known locations written on her artificial leg “I get a new leg every two years and I can choose the design on it. One day I had a sudden thought to get a chalk-board, "Gallagher said. "My mum and grand-mother weren't too keen on the idea, but my friends thought it was great and told me to go for it, so I did.”

    Gallagher said people often stare when she's writing on her leg, but once she shares the photos she receives only positive feedback. "My leg hasn't stopped me from doing anything I've wanted to do," she said. "I don't know if it's my determination to prove to myself that I can do it, but regardless, I've been able to keep up with my peers and lead a pretty great life, Gallagher shows us that you should never let anything stand in the way of your dreams. And if life gives you an artificial leg, make art