Three kinds of bears live in the United States. They are the black bear, the brown bear, and the polar bear.

    Black Bears

    Black bears are the most common of the three. They live in forests in many different parts of the country. Even though they are known as black bears, they are not always black. Sometimes they are brown or tan (黄褐色的) , and a few are even white. Black bears are usually about five or six feet long, and they are the smallest of the three kinds of bears.

    Brown Bears

    Brown bears are found in a few western states and in Alaska. They live in forests as well as in open areas called the tundra (冻土地带). Brown bears are usually light or dark brown and can grow to be very large. In fact, some are eight feet long!

    Polar Bears

    Polar bears can be found in Alaska. It is in a cold area near the North Pole called the Arctic and there are no trees there. Polar bears are white, and they are the largest of the three kinds of ears. They are a little longer and usually heavier than the brown bear.

    Other Interesting Things

    Bears eat different things. Black and brown bears eat fish and other kinds of meat, roots, and berries. Polar bears eat fish, other meat, seaweed, and grass. All three types of bears eat as much food as they can find just before winter. Then during the cold months, they sleep in caves or hollowed-out trees called "dens". They keep them warm. Winter is when the female bears have their babies. All three types of bears have between one and four cubs (幼兽). The cubs are born while the mother bear sleeps!

    All people are afraid of bears. However, bears are actually shy. Most bears try to stay away from people, but still, bears can be dangerous at times.

    Deserts are found where there is little rainfall or where rain for a whole year falls in only a few weeks' time. Ten inches of rain may be enough for many plants to survive (存活) if the rain is spread throughout the year, If it falls within one or two months and the rest of the year is dry, those plants may die and a desert may form.

    Sand begins as tiny pieces of rock that get smaller and smaller as wind and weather wear them down. Sand dunes (沙丘) are formed as winds move the sand across the desert. Bit by bit, the dunes grow over the years, always moving with the winds and changing the shape. Most of them are only a few feet tall, but they can grow to be several hundred feet high.

    There is, however, much more to a desert than sand. In the deserts of the southwestern United States, cliffs (悬崖) and deep valleys were formed from thick mud that once lay beneath (在……之下) a sea more than millions of years ago. Over the centuries, the water dried up. Wind, sand, rain, heat and cold all wore away at the remaining rocks. The faces of the desert mountains are always changing--very, very slowly--as these forces of nature continue to work on the rock.

    Most deserts have a surprising variety of life. There are plants, animals and insects that have adapted (适应) to life in the desert. During the heat of the day a visitor may see very few signs of living things, but as the air begins to cool in the evening, the desert comes to life. As the sun begins to rise again in the sky, the desert once again becomes quiet and lonely.

    Today more and more children wear glasses before going to middle school. They keep their eyes watching TV or playing computer games for a long time. Eyes are the windows of our hearts (心). We use our eyes to see everything around us, so we should know how to protect our eyes.

    Love our eyes. When we open (睁开) our eyes every day, we can see the lovely friends and parents, beautiful flowers and green trees. If our eyes don't work, how can we see the world. In our eyes, everything and everywhere is dark. It's like a house with no light (光). How important our eyes are!

    Relax our eyes. First, stop to relax 30 minutes when using the computer for an hour or two. Next, remember to do eye exercises every day. Then, looking at green trees also helps a lot. In these ways, our eyes will feel relaxed.

    Have good habits. When writing homework and reading, it is important to keep a distance (距离) of 30 cm between your eyes and books. Remember to use our eyes in a right way. Don't read in bed or on a moving bus. Eat something healthy for eyes, such as carrots, fish and eggs.

    Follow my advice (建议) and get good habits. It's time to say goodbye to thick (厚的) glasses.

    Benjamin Banneker was born a few months before another great American—George Washington. Benjamin was black, but he was not a slave (奴隶). He and his mother and his grandmother were free. Benjamin's grandmother came from England. In America she got a job and worked for many years to pay for her boat trip across the ocean. After working many years, she saved enough money to buy a farm. Benjamin lived with her for a while. She taught him to read, write and do arithmetic (算术).

    Benjamin's neighbours knew that he was clever. They were not surprised when he built a large wooden clock. He made each piece after studying a small pocket watch. The clock made him famous, for it was one of the first clocks built in America. People from other places began to send hard problems of all kinds to Benjamin to settle.

    Thomas Jefferson heard of Benjamin Banneker's ability to settle hard problems. He asked Banneker to help build the city that was to be the capital of the United States—Washington, D.C. Banneker worked hard on the plans for the city. He marked where the streets and buildings—the Capitol (美国国会大厦), the White House, and many other places should be built.

    Later, L' Enfant, the Frenchman who had designed the new city, had a quarrel, and went back to France in anger. He took all of the plans away. The workmen couldn't build without any plans to follow.

    For a while it seemed that the plans for the capital might have to be changed, but Benjamin Banneker remembered the plans he had helped draw. He drew each again as he had built each piece of his clock.

    If it weren't for Benjamin Banneker, Washington,

    D.C might look very different from the way it does today.

    Imagine one day, the water taps in your house stop running. You have to buy water from shops. And still there {#blank#}1{#/blank#}water for everyone. Your mother has to save the family's shower water to do other things. Would you be able to stand that kind of life?

    Probably not. But that's what kids in Yemen are experiencing. Experts said Yemen is going to be the first country in the world to run out of water. {#blank#}2{#/blank#}a report, the capital, Sana'a, will run out of drinking water as early as 2025.

    Because of the shortage, the government often cuts the water supply. Hannan, an 18-year-old girl from Lahej, told the Times: "In a good week we'll have the water supply all week. But then the following week there will be water only for {#blank#}3{#/blank#}."

    Hannan said only rich people have enough water to use. They can buy water from the shops or from the water trucks. Private companies own the trucks. They {#blank#}4{#/blank#}every day to sell water—at very high prices. "A lot of people can't afford it," she said.

    The government is {#blank#}5{#/blank#}making use of seawater. But it will cost a lot and it may not happen soon enough to help the people of Yemen.

    Most teens need more than 9 hours of sleep each night. But about 1 in 4 teens has trouble in sleeping. Lack of sleep can affect everything from our feelings to how well we focus on tasks like studying. It can also influence sports performance, increase our chances of getting sick, and may lead to weight gain in some people.

    How can we get the sleep we need? Here are some ideas:

    Be active during the day. Get at least 60 minutes of exercise a day. Physical activity can decrease stress and help people feel more relaxed. Just don't work too close to bedtime because exercise can wake you up before it slows you down.

    Say goodnight to electronics. Experts suggest using the bedroom for sleep only. At least shut everything down an hour or more before lights out.

    Keep a sleep routine. Going to bed at the same time every night helps the body expect sleep. Creating a bedtime routine can improve this relaxation effect. Reading, listening to music, spending time with a pet, writing a diary or doing anything else can relax you.

    Expect a good night's sleep. Instead of worrying that you won't sleep, remind yourself that you can. Say "Tonight, I will sleep well." several times during the day. It can also help to practise breathing exercises or gentle exercises before bed.

    Everyone has a sleepless night once in a while. But if you regularly have trouble in sleeping and you think it's affecting your mood or performance, talk to your doctor.