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.

What should you do if there's an earthquake（地震）at school？ How can you save yourself when you are caught in a stampede（踩踏）？March 25 this year provided you with something about safety（安全）. 

This day is called the National Day of Education on the Safety of Elementary and Middle School Students（NDESEMSS）（全国中小学生安全教育日）. The topic of the day this year is to help students learn more about safety and make sure their lives safe. A survey shows that school accidents kill more students than anything else. The main accidents come from stampedes, earthquakes, fires and sports injuries（伤害）. What can we do to keep ourselves safe？ Staying calm（冷静的）is the first and most important rule when facing accidents. But we have different advice on different accidents. 

A stampede is possible anywhere. The more people get together, the more likely stampedes are to come. When students around you begin to push, you should stand still and try to hold onto something, or stay in a corner until the crowd leaves. If you fall down in a moving crowd, cover your head with both hands. 

Earthquakes are common. When you feel the ground shake, drop down, take cover under a desk and hold on. You should stay indoors until the shaking stops. If you are outdoor, don't stay near buildings, trees or power lines. 

When there's a fire, follow the teachers' words, leave the classroom quickly and use a piece of cloth to cover your mouth and nose so that you don't breathe in smoke. 

If you have difficulty managing time wisely, here comes a wonderful way to solve it--a timer, Generally speaking, a timer has two functions, including the count-up (正计时) one and the countdown (计时) one. {#blank#}1{#/blank#}

For the count-up function, it can help you feel a sense of achievement, All you need to do is to turn it on at the beginning of the tasks. {#blank#}2{#/blank#}In this case, you can also easily find out how much time has been spent on each task as well. As for the countdown function, it is also of great help, especially when you can hardly pay full attention to your own task. {#blank#}3{#/blank#} What you only need to do is to focus on the things you . are doing right now without thinking about anything else. 

How can we use the timer in our daily life? First, it can help us with study. {#blank#}4{#/blank#}

If we set 25 minutes to finish one part of an English test, we can check afterward to make comments on bow well we have done, hat's more, it is also useful in daily lives. {#blank#}5{#/blank#}It can remind us to check on the food and avoid overcooking. 

Nowadays, many people visit museums. They offer great chances for people {#blank#}1{#/blank#}(learn) about different cultures as well as the development of history. 

At the same time, more and more popular design(设计) museums are opened today. Unlike most museums, they show our daily objects, such as fridges {#blank#}2{#/blank#} washing machines. The advantage of design museums is that they are places where people feel familiar with the exhibits. Unlike other museum {#blank#}3{#/blank#}(visitor), people seldom feel afraid or lost when they visit the design museums. This is partly because design museums {#blank#}4{#/blank#}(clear) show how and why mass(大批的) products work and look as they do. 

So far, several new design museums {#blank#}5{#/blank#}(open) their doors. Each has tried to satisfy the public's growing interest {#blank#}6{#/blank#} the field with new ideas. 

London's Design Museum, for example, shows {#blank#}7{#/blank#} collection of mass-produced objects. {#blank#}8{#/blank#}(thousand) of people visit it every year. The choices open to design museums become {#blank#}9{#/blank#}(wide) than ever before. People may also sense the humorous part of our society while {#blank#}10{#/blank#}(walk) around such an interesting museum. 

A lot of animals travel from one place to another. We call this migration. 

In Africa, large animals, like elephants and zebras, migrate to find food and water. They usually follow the same ways every year. 

A lot of birds migrate to find food and better weather, too. They are usually birds that eat insects. They spend the summer in northern Europe, because there are lots of insects there. In the winter there aren't any insects, so the birds fly south to southern Europe and Africa. 

Some insects migrate, too. In North America, millions of monarch butterflies fly south to spend the winter in Mexico, California and Florida, where it's warmer. They travel 50-65 km each day and they travel about 1,125 km. 

Some fish migrate to breed (繁殖). Salmon (鲑鱼) can swim over 20,000 km in their life. They are born in rivers in Ireland, Scotland and other places in northern Europe. The young fish swim down the river to the sea and into the Atlantic Ocean. They live in the ocean until they are adults. Then they return to the river where they were born. They lay their eggs in the river and then they usually die. Salmon do this, because their eggs are safer in the river. Other fish can't eat them. 

Arctic terns (北极燕鸥) travel the furthest when they migrate. They spend the summer in the Arctic, but when winter comes they fly to the Antarctic, because it's summer there. The next year they fly back to the Arctic again. In one year these small birds travel 36, 000km from one end of the earth to the other and back again. Nobody knows how they do it.