当时身无分文的J·K·罗琳坐在火车上，脑子里有了这个想法，她把这个想法构思成共有七本书的系列，每书写的是在霍格沃茨魔法学校里的一年发生的事。

She imagined his story as a series of seven books, each spanning a year at the Hogwarts School of Witchcraft and Wizardry.

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尽管制造燃料电池的成本居高不下，罗安表示这一成本近两年来已经下降了30%。

And while the costs of making fuel cells remain high, Roan said they "ve dropped by 30 percent in the last two years."

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