But then I found a book in the school library that told you how to make a bright purple solution turn bright green, just by passing it through a funnel of filter paper.

• 但是后来我在学校图书馆里找到一本书，书上告诉你如何制备一种淡紫色的溶液，只须用一个铺有滤纸的漏斗过滤一下就可以变成浅绿色。