Do you know some great inventors and their inventions?

    What factors (因素) are needed for their success?

    Well, good timing for a start. You can have a great idea which the public simply doesn't want … yet. The Italian Giovanni Caselli invented the first fax（传真）machine in the 1860s. Although the quality is excellent, his invention quickly died a commercial(商业的) death. It was not until the 1980s that the fax became very common in every office… too late for Giovanni Caselli.

    Money also helps. The Frenchman Denis Papin (1647-1712) had the idea for a steam engine （蒸汽机）almost a hundred years before the better-remembered Scotsman James Watt was even born… but he never had enough money to build one.

    You also need to be patient (it took scientists nearly eighty years to develop a light bulb which actually worked)… but not too patient. In the 1870s, Elisha Gray, a professional inventor from Chicago, developed plans for a telephone. Gray saw it as no more than “a beautiful toy”. However, when he finally sent details of his invention to the Patent Office(专利局) in February，1876, it was too late. Almost the same invention had arrived two hours earlier and the young man who sent it , Alexander Graham Bell, will always be remembered as the inventor of the telephone.

    Of course what you really need is a great idea—but if you haven't got one, a walk in the country and a careful look at nature can help. The Swiss scientist, George de Mestral, had the idea for Velcro(魔术贴) when he found his clothes covered in sticky seed pods after a walk in the country. During a similar walk in the French countryside some 250 years earlier, Rene Antoine Ferchault de Reaumur had the idea that paper could be made from wood when he found an abandoned wasps' nest(蜂巢).

    You also need good commercial sense. Willy Higinbotham was a scientist doing nuclear (核能的)research in the Brookhaven National Laboratory in Upton, USA. In 1958 the public were invited to an exhibition in the Laboratory to see their work, but both parents and children were more interested in a tiny 120cm screen with a white dot which could be hit back and forth over a “net” using a button and a knob. Soon hundreds of people were ignoring the other exhibits to play the first ever computer game—made from a simple laboratory instrument called an “oscilloscope”. Higinbotham, however, never made money from his invention: he thought people were only interested in the game because the other exhibits were so boring!

    What does it mean to be green? "Green" is more than just a color. It also means taking special steps to protect the environment — the water, the land, and the air we breathe. Why green? Plants are green, and without them the earth wouldn't be such a lovely home for us human beings.

    Sometimes people call our society a "throwaway society". That means we are always throwing away old things and buying new ones. Many times, if you no longer need something, someone else just might need it. For example, if your brother is old enough not to play with his plastic bike, why not give it to another family who has a little kid so that they don't need to buy one? And one less large plastic toy doesn't need to be produced.

    Recycling （回收利用）has never been easier. Many organizations will pick it up right in front of your house and some towns even require （要求）it. Tell your mom or dad you want to become "Chief of Recycling" for your family. Now that you know what things you can recycle, find a place to keep them. Make sure you encourage everyone in your house to think whether things can be reused or recycled before they're thrown away.

    Almost everyone likes traveling. But next time before you travel around the world, take a look at your own backyard. Is there a place where you could plant a tree or put in a little fruit or vegetable garden? If so, get there and get your hands dirty. Then you can watch with pride as your tree takes root, and your garden plants grow into big plants full of ripe, red tomatoes or tiny, juicy blueberries. Who knew being green would taste so good?

    Space vegetables are grown from seeds(种子) that have been taken to space and brought back to the earth. The seeds are affected by the radiation(辐射)and low gravity in space. When they are brought back to the earth, these seeds produce vegetables that are bigger and healthier than normal vegetables. However, some people worry about eating space vegetables. They think that space vegetables might not be good for us and could make us get sick because of the radiation in space. However, people should not be frightened because space vegetables are very healthy.

    Here are some facts that you should know about space vegetables.

Space vegetables are grown from seeds that are carefully chosen. When seeds are brought back from space they are tested to make sure that they will be safe to eat.

    Space vegetables are better for you than normal vegetables. For example, space tomatoes stay fresh for twenty days, which is one week longer than normal tomatoes。

    After genetically modified (转基因)food appeared in the market, people worried that they were eating unknown things. For example, if nut genes(坚果基因) are put inside potatoes, people allergic(过敏的) to nuts might get sick from eating these potatoes because they do not know they are also eating nuts. Unlike genetically modified food, space vegetables have not been genetically changed. This means that no new genes are put into the vegetables. Therefore, there are no dangers of eating unknown.