汉语中的“对字句”有其特殊的句法表现行为和内在的结构复杂性,值得研究。本文以Chomsky的最简方案为视野,揭示“对字句”中缘何出现“对”和“作”的动因,认为“对”字的嵌入是为了给前置宾语指派格,“作”字的嵌入也是为了指派格,但“作”是一个轻动词,不具备指派论旨角色的能力,再者,在“对字句”中,类似于“调查”这样的词的语类具有名词和动词的混合特性。 Chinese “对 句” has its special syntactic behavior and inherent structural complexity, which deserves to be studied. In this paper, Chomsky’s Minimalist Plan is used as a field of vision to reveal the motivation for the occurrence of “对” and “作作” in “对 句”. The embedding of “对” is meant to assign the frontier with “格” and “作” It is also for the purpose of assigning a cell, but “作” is a light verb and does not have the ability to assign the role of a decisive factor. Furthermore, in the “right sentence”, the categories of words like “survey” have the mixture of nouns and verbs characteristic.