[] the period during which a product, a project, or an organization exists; the developments and changes which occur during this period（产品、方案、机构的）生命周期◆the natural life cycle of new businesses新企业的自然生命周期◆The tasks will vary over the life cycle of the project.这些任务随项目的生命周期而有所不同。◆These models are nearing the end of their life cycles.这些型号快要被淘汰了。product life cycle