Often, you have two documents in memory and you would like to merge or include a part of one document into another.
通常，您会希望合并内存中的两个文档或者将一个文档中的部分内容加入到另一个文档中。
2
Perhaps your organization's habit with PDF is to have someone adept with a particular desktop word processor set up a "mail merge" sort of operation to parameterize document output.