Use Case editor to create use-case specifications and use-case diagrams;

用例编辑器 以创建用例规格和用例图；

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As we move from use case diagrams into sequence and class diagrams, we will immediately notice the impact of known actors.

当我们从用例图转入到序列图和类图时，马上就会注意到已知的参与者的影响。

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One way this occurs is by confusing data flow diagrams with use case diagrams.

发生的方式之一是将数据流图和用例图混淆在一起。

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