If条件句作为一项重要的语法内容引起不少学者的关注,从传统语法的角度进行分析解释的文献不在少数。本文尝试从“心理空间”这一认知视角对If only和Only if这两个条件状语从句中的特殊结构进行分析讨论,揭示这两个特殊条件句结构背后的认知理据,不仅能够体现出“心理空间”理论的阐释力,同时对我们更好地了解和掌握这两种特殊结构以及其他一般性条件状语从句结构具有一定的启示意义。 If conditionals as an important grammatical content has attracted the attention of many scholars, from the perspective of the traditional grammar analysis of the literature is no small number. This paper tries to analyze and discuss the special structures of If only and Only if from the cognitive perspective of “psychological space ”, reveals the cognitive motivation behind these two special conditional clauses not only can It reflects the explanation power of the theory of “psychological space” and has certain enlightenment for us to better understand and grasp these two special structures and other generic conditional adverbial clause structures.