语义词汇收官：从整段构建可检索图

章末能力：从整段构建可检索语义图

收官课把词义、搭配、角色和逻辑压缩成一张图。目标不是收集所有生词，而是让核心词能通过关系互相唤起，并直接服务题目。

自拟材料

The city piloted a deposit scheme for reusable containers. Customers paid a small charge and recovered it when they returned the container. Early participation was uneven because collection points were scarce. After retailers expanded the network, return rates rose and the city extended the scheme.

建图步骤

对象：deposit scheme；角色：city、customers、retailers；动作链：pay → return → recover；障碍：scarce collection points；修正：expand network；结果：return rates rise；决策：extend scheme。

deposit 与 charge 关联但不是永久费用，因为 returned 后 recovered；scarce 与 expanded 形成数量反向；pilot 与 extended 构成试行到扩大。

错解反馈

若把 deposit 当罚款，会无法解释 recovered；把 uneven 当失败，则忽略后续网络扩展与回收率上升。语义图必须能容纳全文变化。

正文练习

Why did return rates rise?

A. Deposits became permanent. B. Retailers increased collection access. C. Customers stopped returning containers. D. The pilot ended immediately.

**答案：B。**expanded network 改善 scarce points。

独立验收

不看正文复画七节点语义图，用它解释 deposit、scarce、pilot、extend 四词，并完成题目。只列词义不通过。