Identify types of relationships . consider degree , optionality , multiple relationships , and exclusive groups 考虑程度、强制性、多方关系及专用组别等，来认定关系的种类。
2.
In an ideal world , where specifications contain no optionality or ambiguity , a profile would be just a list of specs that compose together to achieve a given function 在理想的情况下，规范没有可选性或多义性，概要应该是为实现给定功能而组合到一起的规范的列表。
3.
You made this element optional for backward compatibility , but you ll notice that the optionality of this field is a good idea anyway , because not all addresses have apartment numbers 您可以使这个元素为向后兼容的可选项，您会发现这个字段的这个可选性是一个很不错的主意，因为并不是所有的地址都有房间号码。
4.
The primary motivation is to improve the potential for interoperability by constraining optionality of the underlying specifications and providing guidance as to how the various specifications compose with each other 制定的。主要的动因是为了通过约束基础规范的可选性和提供有关各个规范如何组合的指南，以提高互操作性的潜力。
