The（1）is a general description of the architecture of a workflow management system used by the WFMC,in which the main components and the associated interfaces are summarizeD） The workflow enactment service is the heart of a workflow system which consists of several（2）.空白(1)处应选择（）
- AA.waterfall model
- Bworkflow reference model
- Cevolutionary model
- Dspiral model