Taking sea target surveillance and hitting system for example, the top-level demands are described using user case diagram, class diagram, activity diagram and collaboration diagram in UML.

以海上目标监视与打击体系为例，给出利用UML中的用例图、类图、活动图、协作图对体系顶层需求进行描述的方法。

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We also accompanied each item in the diagram — use case, business object, user, or whatever — with a line or two of text describing that item's purpose.

我们也为图中的每一项提供了文档—用例、业务对象、用户或者其他项—用一到两行的文字来描述每一项的目的。

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Depending on the selection (Source in this case), the number of options available changes on the menu that pops up when the user drops the cursor on the Diagram surface.

依赖于用户的选择(本实例中为Source)，当用户在图表上下移光标时，弹出菜单上可用选项的数量会随之改变。

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