1·For example, it is possible to express that InvoiceType (type of Invoice number) cannot be subtyped, that is, no one can define a new version of InvoiceType.
比如，有可能表示InvoiceType (Invoice编号的类型)不允许子类型化，任何人都不能定义新版本的InvoiceType。
2·These basic types can themselves be subtyped to define new kinds of content, and it’s typical to define subtypes of a document for a specific kind of business.
这些基础类型自身可以用作子类型来定义一种新的内容，最典型的是为某种特定业务定义一个文档的子类型。
3·Step through the creation of subtyped entities and three service types that may consume them (add, update, and inquiry by identifier) with performance considerations in mind.
了解创建子类型实体和使用它们的三种服务(添加、更新和按标识符查询)的步骤，同时考虑性能因素。
4·Gain insight into the structure of Master Information Hub entities and services, and the possibilities you have to customize the implementation of a subtyped entity and its services.
了解Master Information Hub实体和服务的结构，以及如何定制子类型实体及其服务的实现。