（）is a method used in Critical Path Methodology for constructing a project schedule network diagram that uses boxes or rectangles， referred to as nodes， to represent activities and connects them with arrows that show the logical relationships that exist between them.
PDM 用于关键路径法，是用于编制项目进度网络图的一种方法，它使用方框或者长方形（被称作节点）代表活动，它们之间用箭头连接，显示彼此之间存在的逻辑关系。