To recap my scenario, I want to enable my users to navigate a set of articles using a natural hierarchy.

为了重述我的案例，我想要让我的使用者巡览的一组使用自然阶层架构的文件。

youdao

By that logic, my hierarchy is simply a projection over a set of articles-and this changes my model such that I have a clearly defined, single article aggregate, as shown above.

由该的逻辑我阶层会是只要投影文件的集合，此变更我的模型，如上述所示，我有一个清楚定义的单一文件，汇总。

youdao

Readers will be required to pay when they have exceeded a set number of its online articles per month.

当读者每月在线（阅读）文章超过规定数量时，他们将被要求付费。

youdao

You can set up a list of contacts and send them articles.

FORBES: Magazine Article

In a series of articles in the Lancet timed to coincide with the Olympics, researchers from 16 countries set out the scale of the health burden created by physical inactivity.

BBC: Sedentary lifestyle can kill

For 20 years, federal health and justice officials have concocted and applied a warped set of legal principles which essentially prohibit medical product makers from sharing truthful information (even peer-reviewed journal articles) with doctors about off-label uses.

FORBES: The Dangers Of Information Restrictions On Drugs' Off-Label Uses