Feasibility should be measured throughout the life cycle of system development. The scope and complexity of an apparently feasible project can change after the initial problems and opportunities are fully analyzed of after the system has been designed. Thus,a project that is feasible at one point may become infeasible later . The first feasibility analysis is conducted during the（preliminary investigation phase）. The（decision analysis phase）represents a major feasibility analysis activity since it charts one of many possible implementations as the target for systems design. （Operational feasibility）is a measure of how well the solution will work in the organization. It is also a measure of how people feel about the system. When it is determined in the later stages of the system life cycle,（usability analysis）is often performed with a working prototype of the proposed system. This is a test of the system's user interfaces and is measured in how easy they are to learn and to use and how they support the desired productivity levels of the users. Economic feasibility has been defined as a cost-benefit analysis.The（payback analysis）technique is a simple and popular method for determining if and when an investment will pay for itself.
系统开发生命周期全程需开展可行性分析，项目的可行性会随阶段推进发生变化，前期可行的项目后续可能因问题深化、方案设计调整转为不可行。各阶段的可行性分析侧重不同：初始调研阶段是首次开展可行性分析的环节，用于初步判定项目是否具备推进价值；决策分析阶段核心是对多套候选实现方案进行可行性对比评估，最终确定系统的设计方向；需求分析阶段则聚焦用户需求的梳理与验证，为后续可行性分析提供细化依据。
可行性分析主要涵盖四类核心维度：运行可行性关注方案在组织中的适配性及用户接受程度，直接关系到系统落地后的实际运行效果；技术可行性评估现有技术手段能否支撑方案实现；进度可行性判断项目是否能按预定时间节点完成；经济可行性围绕成本与效益展开分析，评估项目的投入产出合理性。
在系统生命周期后期，通常会通过可用性分析验证运行可行性，借助可运行原型对用户界面进行测试，重点衡量界面的易学性、易用性，以及对用户生产力水平的支撑能力。
经济可行性分析中有多种方法，其中回收期分析是简单且广泛应用的方法，可直观判断投资成本的回收周期；投资回报率分析、现值法属于更复杂的财务评估方式；货币时间价值是这类经济分析方法的底层经济学原理，并非具体的可行性评估方法。
本题考察的是系统开发生命周期中的可行性分析。
语境定位：原句为 “The first feasibility analysis is conducted during the ____ The”。空前 feasibility analysis is conducted during the；空后 The 是判断本空的关键。
答案判断：从语法看，这里需要名词或名词短语；从语义看，应填“初步调查阶段，项目早期评估可行性”。因此应选 preliminary investigation phase。
选项辨析：
A. problem analysis phase：问题分析阶段主要是识别和理解问题，不是第一次进行可行性分析的阶段，错误。
B. preliminary investigation phase：初始调研阶段是系统生命周期中进行第一次可行性分析的阶段，符合语境。
C. requirements analysis phase：需求分析阶段主要明确用户需求，已经晚于第一次可行性分析，错误。
D. decision analysis phase：决策分析在后续阶段才进行，不是第一次，错误。
因此，选项 B 正确。