题目：
The Rational Unified Process (RUP) is a software engineering process, which captures many of best practices in modern software development. The notions of (21) and scenarios have been proven to be an excellent way to capture function requirements. RUP can be described in two dimensions - time and content. In the time dimension, the software lifecycle is broken into cycles. Each cycle is divided into four consecutive (22) which is concluded with a well-defined (23) and can be further broken down into (24) - a complete development loop resulting in a release of an executable product, a subset of the final product under development, which grows incrementally to become the final system. The content structure refers to the disciplines, which group (25) logically by nature.
25（）
A.functions
B.workflows
C.actions
D.activities
答案：
参考答案：D
解析：
参考译文如下。
RUP (Rational Unified Process)是一种软件工程过程产品，它吸取了现代软件开发中许多成功的实践。事实证明，采用用例( use-cases)和剧情（scenarios）捕获目标系统的功能需求是一种较好的办法。可以采用二维模型来描述RUP—时间和内容。从时间维来看，软件生存周期被划分为不同的周期(cycles)。每个周期又被划分为4个连续的阶段( phase)，每个阶段都包含一个妥善定义的里程碑(milestone)，每个阶段还可以被进一步划分为若干轮迭代(iterations)。一次迭代是一次完整的开发过程，每次迭代结束时会发布一个可执行的产品，这个产品是正在开发的软件系统的一个子集，它会逐渐扩展为最终系统。内容结构指的是一些将活动( activities)组织在一起的、天然存在的规则。
