问题描述：
描述一下并写出原因
最佳答案：
我想发明一种全自动书包，你可别小看它，它的旁边有三个按钮，有什么用处呢？听我给你——介绍。
一个按钮用处可不小呢！只要按下它，书包里的重量会立刻减轻，放学时你就可以轻轻松松的回家了。第二个按钮可以帮助你整理刷洗书包，就不用你自己整理了。第三个按钮只要按下它，就会发出娓娓动听的音乐，你会感到轻松愉快。
这种书包的价格便宜，如果你高价出卖的话，功能会全部消失。我相信随着科学的发展，通过我们的努力，一定会成为现实。
I want to invent a kind of automatic schoolbag, you can't look down upon it, there are three buttons beside it, what is the use? Let me introduce you.
A button is a lot of use! As long as you press it, the weight in your bag will be lightened immediately, and you can easily go home when school is over. The second button will help you clean your bag without having to do it yourself. The third button will make you feel relaxed and happy as long as you press it.
The price of this kind of schoolbag is cheap, if you sell it at a high price, the function will disappear completely. I believe that with the development of science, through our efforts, it will become a reality.
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