The twenty first century is really fast and forces us to move faster with the pace(步伐) of it. The smartest way to shop nowadays is online shopping.

    Online shopping saves our precious time. It frees us from unpleasant visits to the shops. We don't need to travel long distances under the hot sun or the pouring rain. Just turn on our personal computers and a simple click will bring us into a magic world.

    It is very convenient(方便的) way of shopping because we can choose the product from a large range(范围) and we get to know the new products. We can see almost all products that we need online. There is food for people and pets， clothes， tools， books and magazines， electronic equipment， souvenirs and many others.

    Things in online stores are cheaper than those in big stores. There are always sales and special offers. With so many stores on line， we can take our time to make a comparison(比较) and choose the lowest price. There is also a possibility to pay by check or credit card(信用卡).

    Besides shopping on line， we can conduct(经营) our sales on line too. Is your family considering(考虑) replacing the old television that does not fit in your new home setting? Then why don' t you try to sell through Internet? Yes， even you can sell your products or un-wanted things through online shopping. You don't need to have your own personal e-commerce site. You can sell it through free ad posting sites. You will find plenty.

    With the latest technology， we have the best chance to shop online and feel the pleasure. You haven't tried it yet? Go and get a true online shopping experience now!

    The population of Earth is still going up. There will be less and less good land for growing crops in the future. People worry that there will not be enough food for everyone in the middle of this century.

    Recently scientists have discovered one strange plant named fedtschenkoi（玉吊钟）may help. It can absorb（吸收）carbon dioxide(CO₂) at night. It only needs 10 times less water than food plants like beans. This means it can grow in the desert(沙漠).

    In which ways could this plant help us?

    Since deserts are increasing in size because of the changes in Earth's climate, growing plants there will be more and more important. Although it is dangerous to eat this plant, scientists can still study something about it: how it absorbs CO₂ at night while many other plants only do this during the day, and why it is suited to the desert.

    There is another direction to take the research in. Producing a desert plant to eat will be difficult, but there is still possibility to use the genes(基因)from this plant and put them into food plants.

    The other way is to grow this type of plant for fuel(燃料). At the moment we grow plants for fuel in good land. If we do it in deserts instead, more good land can be used to grow plants for food.

    Desert plants have special qualities, which could be an answer to our future food or energy needs. Scientists are working hard on it.

    The train made a lot of noise as it came to a stop at the station. Martha waited for a while until her father held her hand. They walked onto the train together. Her mother and brother walked behind them.

    This was the first train ride for Martha and her brother Brian. They would take the train to visit their grandparents. They usually went there by car. But today, Mum and Dad wanted to try a different way.

    They walked to the middle of the train. They found some seats and sat down. A few minutes later, the train began to move.

    Martha and Brian felt a little nervous, but their parents said they would enjoy the ride. Dad said he liked the train ride because he didn't need to drive all the time. Mum added that she could talk to her two children face to face instead of turning around.

    When the children their parent's words, they felt relaxed.

    "The train isn't as noisy as I thought would be" said Martha,“ and I can stand up and walk around. I believe I can see everything through the windows.”“The train really goes fast," said Brian," I like that best of all. If we get on the train in the morning, we can see grandparents before lunch. I can't wait to enjoy their apple pie!"

根据短文内容回答下列各题。

You are what you eat

    Keeping better eating habits can help you reduce (减少) disease (疾病). A healthy eating plan means choosing the right foods to eat and preparing foods in a healthy way.

    ____________

    Do you often change your toothbrush？Maybe you think it is not necessary. A study shows old toothbrushes bring disease. You should often change your toothbrush.

    Exercise

    Swimming, running, skating, skiing, dancing, walking and some other activities can help you stay healthy. You should exercise at least three times a week and for twenty minutes or more each time. Do it.

    Plan out your life

    You should have breakfast before you go to school. Have a proper (合适的) meal for lunch. Follow a healthy diet.