When some plates(板块)of the Earth move suddenly, an earthquake happens. Many earthquakes begin under the sea. Earthquakes may happen anywhere on the Earth. They often happen near the mountains.

    During an earthquake, the shakings make rocks rise suddenly and even crack(断裂) open. Houses fall down. People are killed or hurt, and sometimes the whole villages or cities are destroyed.

    Can we do something to keep ourselves safe from earthquakes? Scientists have studied earthquakes and made maps that show the “earthquake belt（带）”. In area of these belts, it's possible for earthquakes to happen. In these areas we should build strong houses to fight against earthquakes.

    In the future, Scientists will be able to tell when and where an earthquake will attack before it happens. They can also tell people what to do and how to deal with it.

    You don't have to be a weatherman to tell people about the weather. If you notice the animals, the sky and the world around, you can predict weather on your own.

    Examine the moon or sun, but do not look at the sun directl or it will hurt your eyes seriously. If you see a ring around the sun or moon, then warm weather follows. A golden ring around the moon warns us that a storm is on the way. A watery yellow sunset is a sign that rain may be near. Feel the direction of the wind. A wind blowing from the east shows that a storm will probably happen. A wind from the west means a sunny day. Monitor the clouds. There are three things about clouds you should look for: movement, color, and change. As a rule , the higher the clouds, the better the weather.  And the lower the clouds , the worse the weather will be.

    The rainbow has a message, too. If you see the sun in the east and a rainbow in the west, the rain may be coming your way. If the sun is in the west and the rainbow is in the east, the rain will be moving away from you. Look at your shoes as you walk through the grass in the morning. If the grass is wet with dew (露珠), then you can expect dry weather. But if the grass is dry, then it will be wise of you to take your umbrella.

    You may know about "junk food" like French fries. But do you know about "junk sleep"?

    Recently, a British survey found that electronic products（电子产品）in teenagers' bedrooms are affecting（影响）their sleep. The survey was done among 1,000 British kids from 12 to 16. It found that 30 percent of them got just 4 to 7 hours of sleep every day. But doctors say they need 8 to 9 hours.

    Almost a quarter of the kids said they fell asleep more than once a week while watching TV, listening to music or using other electronic products.

    "This is very worrying." said Dr. Chris Idzikowski, "We call it "junk sleep". It means you don't get enough sleep and the quality（质量）of the sleep is bad, too. If you don't get good rest, you won't perform well in school the next day."

    The survey found that 40 percent of the kids felt tired each day, with girls between 13 and 16 feeling the worst. Nearly all the teenagers have a phone, Mp5 or TV in their bedrooms. And many of them have all three.

    Lidong usually comes on November 7 or November 8 every year. It is the Chinese word for one of the 24 solar terms(节气). It means the beginning of winter.

    As the weather gets colder and there is less sunlight, people might get sick easily. According to scientific research, adults usually have two to four colds each year, while young children suffer from six to eight colds each year, especially in winter months. One of the best ways to keep healthy during winter is to stay warm.

    There are many ways to stay warm. A living room should be around 18-21℃, and you can also use a hot water bottle to keep warm. Getting plenty of exercise is always a good idea to keep your blood moving. Food gives us energy and helps to warm us from the inside. Add some things to your winter dishes, such as pepper, ginger, and garlic. These things can make you warm. A winter coat warms you up from the outside. Add several layers(层) of thin clothing, for example, a shirt and a thin sweater, to stay even warmer. Clothes made from wool are usually very warm.

    How can you make winter days colorful? Is it too cold to play outside? Don't worry. Here are some tips for having fun at home. Give it a try!

    Enjoy a movie with your parents. There are a lot of choices, such as Spy Kids. You can also talk about the movie with your parents after it's over.

    Cook a meal with your parents. You can cook some simple dishes, such as eggs with tomato. You may need your mother's help for the first time.

    Read your favorite book. Reading is not only helpful for your writing ability, but can also help to build your character.

    Sharks(鲨鱼) are the most frightening animals in the sea. Sometimes we can see sharks swimming in the sea around Hong Kong. People put nets around some beaches to protect swimmers. When there is a "shark's flag", people must stay on the beach. It will be too late if a shark can swim sixty kilometres an hour to you.

    There are 30 kinds of sharks and 25 kinds of them are dangerous. The whale sharks are, very big. They can grow to 18 metres long, but they are not dangerous to people. The jaws(大白鲨) and the tiger sharks are the most dangerous kinds of sharks.

    Do you know all sharks must keep swimming, or they will go down?

All sharks can feel everything that happens around them. We must keep calm and don't make any noise when a shark is swimming near you.

    If a shark loses a tooth, a new one will grow out very quickly. So sharks always have many sharp teeth.

    You don't need to get in a time-travelling machine to see how technology will change our lives, such as the way we shop. Several new technologies that are to change your buying habits already appear. Let's see what's in store for your future shopping.

    Try it on, virtually(虚拟地). Want to shop online for a new pair of glasses? You don't need to guess which pair looks best on you—use the eBay Fashion iPhone app to try a pair of glasses you're checking out on a picture of your face. But what about buying something bigger? Thanks to Microsoft Kinect's action tracking(跟踪)camera, you can cover clothes on your screen body. You can even choose the background of your virtual fitting room to improve your shopping experience.

    Get a perfect, custom fit. Everyone's body is shaped differently. To get a perfect fit, you sometimes have to get your clothes changed. But by using 3D scanning technology, all the clothes you buy will fit your body perfectly. Some companies scan(扫描)your body using High-tech to get the real sizes, so they can make special clothes just for you.

    High-tech shopping carts(推车)and checkout counters(收银台). High-tech shopping carts could be common in malls and supermarkets in the future. Microsoft Kinect-enabled carts are under test. The cart can follow you along the aisles(通道), controlled only by your movement and your voice.

    In the United States, several supermarkets use a certain set called "Scan It" that gives buyers the freedom to scan products on their own while they shop. If we don't want to wait in line before the checkout counters, we can use Toshiba's new object Recognition Scanner. The machine identifies(辨认)a product as soon as it's placed in front of a camera just by its shape and color, even if it has no bar code.