2023—2024 论证题：前提、桥梁与结论缺口

能力目标：发现论证缺口

阅读中的推理题常考“证据是否足以支持结论”。论证由前提、桥梁和结论组成；干扰项会把缺失桥梁当成已经证明，或把一个替代解释包装成唯一原因。

自拟短文

After a company redesigned its office, employees reported more informal conversations. Management concluded that the new layout had improved collaboration. Yet the survey was conducted during a month when several teams were preparing a joint product launch, and no measure of work quality was collected.

题目：Which fact most weakens management's conclusion?

A. The office used brighter paint.
B. A joint project may independently have increased conversation.
C. Some employees preferred quiet rooms.
D. The redesign took two weeks.

还原论证

前提是改造后非正式交谈增加，结论是布局改善协作。桥梁假设包括：交谈增加由布局造成，且交谈能够代表协作质量。B 提供替代原因——联合项目本身可能增加交流，直接削弱第一座桥。

C 可能与体验有关，但未直接解释交谈变化或协作；A、D 只是背景。弱化题不是寻找负面词，而是攻击论证所依赖的关键连接。

两个缺口

即使排除联合项目，材料仍未测量工作质量，所以“交谈更多→协作改善”也需要证据。一个论证可以同时有多个缺口，题目要求选择最直接的一项。

迁移练习

哪项新证据最能加强结论？

**参考答案：**在控制项目类型后，使用新布局的团队比旧布局团队表现出更高的共同任务质量。它同时改善因果比较和结果测量。

独立动作验收

写出前提、结论、两座桥和 B 攻击的具体桥梁。只说“样本有问题”不通过，因为没有指出推理断点。