There was an old mule(骡子). One day accidentally he fell into the farmer's well. The farmer thought for a while and said to himself that neither the well nor the old mule was important to him. So he decided to use soil to bury the old mule in the well.

    Then the farmer called his neighbours and they started to put the soil into the well together. The old mule was quite afraid in the beginning. But soon one hopeful idea came to his mind - every time when a shovel(铁铲) of soil landed on his back, he would shake it off and step up!

He said these words to himself again and again, "Shake it off and step up." This way he could fight against the panic (恐慌) and encourage himself. After some time, the mule had stepped over the well's wall. Although terribly tired, he was the winner and he saved his own life. He decided to face his difficulty bravely and not to give up, and finally he won.

    Do you know anything about the invention of the bar code(条形码)?

    A small food store owner found it was difficult to keep records of the product information. In 1948; he contacted the Drexel Institute of Technology to solve this problem. Bernard Silver was interested in it and he set out to look into it. Silver and his students realized their answer in the form of ultraviolet light(紫外线)，ink and a scanner(扫描仪).

    The system did work at first, but it's very expensive and sometimes the system didn't work well. If the invention was to become popular in grocery stores, the problems had to be solved. Finally, Silver solved them.

    The patent (专利权) for the bar code system was asked by Silver and Woodland in 1949. But the patent was not given until 1952. Although this patent was given, the system was still not popular among store owners. In 1966, the system began moving its way into more grocery stores. Logicorn developed the Universal Grocery Products Identification Number (普遍标识号) in 1970. Marsh's superstore in Troy was the first store to set up this bar code reading system. It became very popular ever since, and now it's obviously popular in all types of stores worldwide.

A Small Invention, Big Help

    An invention is an invention - big or small. A big invention makes us feel it all the time, such as the TV and the computer. There are also several small things around us even if we seldom pay much attention to them.

    要求: 语法正确, 语言通顺, 80词左右, 可根据提示内容适当发挥。

提示:

1). 水陆两用汽车: 既可以在陆地上跑, 也可以在水下跑;

2). 这种汽车两侧有两个翅膀, 下面有四个轮子, 在地面上时, 跟普通汽车一样, 但在水下时, 四个轮子会隐藏在车底, 两侧的翅膀会变为两个船桨促使汽车前行;

3). 比一般的汽车更方便、更省油; 节约资源, 减少污染。

生词提示: hide (隐藏), resource (资源), paddle (桨)