He gradually began to see some newspapers, popular science books category, in order to participate in our discussion.

他就慢慢开始看些报纸、科普类读物，以便来参与我们的讨论。

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The inventory information such as book categories and the number of books in each category is displayed in the Web home page (see Figure 1).

诸如书的类别以及每个类别中的书的数量等库存信息将在这个网站的主页(参见图1)中显示。

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Therefore, after updating the data model, you can guarantee that any category without books has been removed and any new category has been added.

因此，在更新了数据模型之后，就可以确保其下没有书的那些类别已被删除并且所有新的类别已被添加。

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Despite a strong selection at competitive prices, the new books category never lived up to expectations, as most of our buyers stayed with their existing retailers (mainly Amazon).

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But until then, they are shaking up nearly every category from books to electronics, as the Amazon Kindle Fire HD will attest.

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The vast majority of books belong to a third category: still protected by copyright, or of uncertain status, and out of print.

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