Menstruation (a period) is a major stage of puberty in girls; it's one of the many physical signs that a girl is turning into a woman.

月经（例假）的来到是女孩青春期中经历的一个重要阶段；它是女孩变为女人的众多生理变化之一。

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Studies in countries such as Ghana and Cameroon suggest many girls at secondary school miss a week of classes when they have their period, or drop out altogether when they reach puberty.

在加纳和喀麦隆等国家开展的研究显示，许多女中学生在例假期间一个星期不去上学，当她们进入青春期，有的甚至辍了学。

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Girls have a growth spurt that slows down with the onset of their first period (for boys, weight and height come in the final stages of puberty).

女孩在首次例假会经历发育激增，之后才会放缓(对男孩来说，体重与身高处于青春期发育最后阶段)。

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