Why do plants grow in some places and not in others? Why does some land have so much growing on it, while other land has almost no plants growing on it at all?

    To grow,  plants need several things. One is warmth. In very cold places almost nothing grows. Plants also need water. In very dry parts of the Earth only a few unusual plants can grow. That's why dry deserts(沙漠) everywhere are almost not covered by trees or grass.

    Plants must also have a place in which to put down their roots and grow. They find it difficult to grow on hard land. The town is built on hard land. The plants here have only the soil(土壤) found between the cracks of the stones to grow in.

    Another thing plants must have before they can grow is food.

    What will happen if we try to make things grow on the sandy beach? A few plants, such as beach grass, will grow in sand, but most plants won't. Even if the weather is warm enough and we water the plants each day, many of them will die because the sand on this beach has almost no plant food.

    In most parts of the world, many students help their schools make less pollution. They join “environment clubs”. In an environment club, people work together to make our environment clean.

    Here are some things students often do.

    ◆No—garbage (垃圾) lunches. How much do you throw away after lunch? Environment clubs ask students to bring their lunches in bags that can be used (被使用) again.

    ◆No—car day. On a no-car day, nobody comes to school in a car—not the students and not the teachers! Cars give pollution to our air, so remember: Walk, jump, cycle or run.

    Use your legs! It's lots of fun!

    ◆Turn off the water! Did you know that some toilets can waste (浪费) twenty to forty tons of water an hour? In a year, that would fill a small fiver! In environment clubs, students mend those broken toilets.

    We love our environment. Let's work together to make it clean.  

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    Every minute，someone is setting up an Internet company somewhere, in the world． Each one is searching for the one great idea that could make his web company click in a big way．And they are trying all kinds of tricks to attract people towards their websites．While some websites offer sounds，cartoons and amazing photos on screen to make their sites almost a movie-like experience for the viewers，others provide free downloads and competitions．

    A company in California，US，has decided to offer online smells to people who visit its website．

    That is，if a pizza image comes on screen，your nose will catch the smell of bread and cheese！All you need to do is to connect a device（设备）called “iSmell” with your computer．This smart little device contains（包含）some chemicals that can create different kinds of smells．

    The company has invented software that changes the chemical composition（成分）of different smells into digital signals(数字信号）．An onscreen image，which is programmed with the proper digital signal，will start the“ iSmell" device．The device will use the software to change' the digital signal again and let go of the correct smell．This device reads the digital smell code（代码）from the website and creates the proper smell from its store of chemicals．This smell is then made to blow softly in the direction of the user with the support of a small fan．

    In order to let go of the correct smell，the company has created a “Scent Registry”，which contains a digital index of thousands of smells．The company plans to allow website developers to integrate（合成）the proper smells in digital code to their games and images．The company is also hoping that Hollywood filmmakers will use the smell technology in their movies．Imagine audiences getting the smell of rocket fuel as a spacecraft takes off on the cinema screen！Of course，filmmakers will have to be careful not to shoot in dirty neighborhoods，which have a lot of rubbish lying around．

    The best way to teach your children to live a green lifestyle is to live that green lifestyle yourself. When kids see you picking up rubbish from the park, they see value(价值)in keeping public places clean Use these tips to introduce your children to green living：

    Use public transport. Use the car only when necessary; at other times, take trains and buses with your children.

    Ask for their help. Younger children often love grown-up activities. So have them carry a small bag of food waste to the bin, or let them help separate(分开)your recycling. Older children may want to take part in the activities like cleaning up the neighbourhood and organizing the daily recycling If they're not very interested, make environment-friendly activities a family-time priority (优先事项)

    _________________________ Petting farms for younger kids may help prevent(防止)farm animals from becoming something that they see only in books or on television. Many people believe that wild animals shouldn't be kept in any kind of zoos, but they do offer a valuable educational and conservation(保护)lesson. So if you want to visit a zoo, find a zoo that provides its animals with as natural an environment as possible

    Our life will be different from nowadays with robots appearing in our homes. So what will the future be like? Here are some students' ideas.