A key one is utility, which refers to the design's functionality: Does it do what users need?

一个重要的就是实用性，即是设计的功能性：它所做的迎合用户需要吗？

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In this example, you will create a use case in your diagram for each of the previously modeled utility classes, since they represent the main functionality of our system.

在此例中，你将会在你的图表中为此前建模的每个工具类创建一个用例，以后它们就代表我们系统的主要功能。

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Different variations of this utility provide varying levels of support and functionality.

此类工具的不同变种会提供不同层次的支持和功能。

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While the above short bullet list may not sound like much, they have truly packed this little board with functionality and utility.

FORBES: How To Program Arduino The Easy Way With Arno Kit