单项选择题 依据项目变更管理流程，项目中的正式变更手续应该由（）来进行审批。

单项选择题 In project management , a (73) is a listing of a project’s milestones, activities, and deliverables, usually with intended start and finish dates. Those items are often estimated in terms of resource (74) ,budget and duration, linked by dependencies and scheduled events.

单项选择题 Circuit-switching technology is used in Publish Switched Telephone Network(PSTN), Global System for Mobile Communications(GSM) and code Division Multiple Access (CMDA) . It is a ( ) information transfer mode.