材料分析题

Of the following pairs of sentences, please tell whether A entails B in each case.
(1) A. Nancy owns three canaries.
B. Nancy owns a canary.
(2) A. John has done his homework.
B. John hasn't brushed his teeth.

【正确答案】

(1) Yes; (2) No

【答案解析】

本题考查狭义的蕴涵关系。狭义的蕴涵是一种纯逻辑推理，即不需要语句以外的背景条件或信息，单就话语本身表达的意义来说有甲就必然有乙的句义关系。根据狭义的蕴涵关系的定义，题干（1）中若A为真，则必然能推导出B，但题干（2）中，句A和句B没有这种关系。